You should note that while having more territory usually does help a country to be more powerful, it is not the only way to be a powerful country. While trying to conquer as much land as possible made sense when agriculture was the primary source of wealth, nowadays it is somewhat more complicated because industry and service sector of annexed territory are often destroyed by the war and has to be rebuilt so why not build in the territory you already own. That leaves natural resources such as oil and coal, but it is sometimes possible to profit from them even without having direct control over them, for example, by owning (directly or indirectly) companies that extract those resources from the ground and having enough influence over the government of that country to prevent them from meddling with those companies. Having higher population seems to be useful in some cases, but wars tend to create a lot refugees and creating an economic union that you dominate is perhaps a good enough substitute. Therefore, it sometimes might not make sense to try to conquer as much territory as possible, especially when that territory does not have a lot of natural resources. I don’t think that NATO and EU are the only things that stop Russia from trying to conquer Baltic States or Finland, they also lack the necessity to do so. Because military force is not the only way to gain a lot of influence over the country’s actions.
In my country (and I would guess in Finland as well), what many people fear is not Russian tanks, it is Russia gaining a lot of influence by making backroom deals, promoting and financially supporting certain political parties and individual politicians whose ideas are useful to them, buying up shares in energy companies, either directly or by proxy individuals (who do not have to be Russians themselves, there are a lot of people who got rich due to having the right connections and they often want to preserve those connections) and gaining cultural influence. Finlandization is often a good enough substitute for the actual conquest. I am not an expert in geopolitics or international relations, but it is my impression that while Crimea does have strategic importance to Russia due its warm deepwater ports, it is harder to make such case for Donbas/Donbass or South Ossetia (or Abkhazia, or Transistria). It is my impression that in these cases it is not necessarily just the territory itself that is important to Russia, but the fact that having disputed territories may make it significantly more difficult for those countries to join NATO and EU, and, that by waging these small scale wars Russia demonstrates ability and willingness to protect their interests, thus sending a signal to many people that Russia is a powerful country and therefore siding with their interests in a domestic politics of their respective countries and trying to establish connections with them is potentially useful. For example, by negotiating with each country individually, Russia is able to extract higher prices for its natural gas than they would be able if EU countries coordinated with each other and negotiated as one bloc. In addition to that, because of these large profit margins, Russia is able to selectively make discounts for some countries in exchange for various things that they want, for example, naval facilities. Thus it is in Russia’s interest to try to weaken the EU, therefore they support various anti-EU parties, politicians (both rightwing and (probably) leftwing) and people who are influential in politics without themselves being politicians in various ways. However, I predict that it would be much more difficult to attract such allies if Russia would give in to Western demands and remove their troops from regions such as Donbas, because it would be interpreted as a sign of weakness, therefore Russia would not be thought of as worth siding with. Even though these anti-EU parties would probably still be anti-EU, they would no longer necessarily be against, e.g. sanctions against Russia. Perhaps even more importantly, there are a lot of influential people in Eastern Europe and Central Asia who find it useful to join whichever side is more powerful and a sign of Russia’s weakness would make the option of seeking closer relations with the West more attractive, thus reducing Russia’s influence even further.
To sum up, in my layman’s view, I do not think that Russia is hungry for more territory, but it is probably hungry for more power and influence over decision making in other countries (because it is a useful thing to have), which can be acquired by other means than conquest. I conjecture that the present situation in Donbas is probably not because Russia desires to annex the Donets Basin, but perhaps because giving in would send a signal that Russia is not strong enough and/or not willing to protect its own interests (let alone interests of their allies), therefore not worth siding with.
You should note that while having more territory usually does help a country to be more powerful, it is not the only way to be a powerful country. While trying to conquer as much land as possible made sense when agriculture was the primary source of wealth, nowadays it is somewhat more complicated because industry and service sector of annexed territory are often destroyed by the war and has to be rebuilt so why not build in the territory you already own. That leaves natural resources such as oil and coal, but it is sometimes possible to profit from them even without having direct control over them, for example, by owning (directly or indirectly) companies that extract those resources from the ground and having enough influence over the government of that country to prevent them from meddling with those companies. Having higher population seems to be useful in some cases, but wars tend to create a lot refugees and creating an economic union that you dominate is perhaps a good enough substitute. Therefore, it sometimes might not make sense to try to conquer as much territory as possible, especially when that territory does not have a lot of natural resources. I don’t think that NATO and EU are the only things that stop Russia from trying to conquer Baltic States or Finland, they also lack the necessity to do so. Because military force is not the only way to gain a lot of influence over the country’s actions.
In my country (and I would guess in Finland as well), what many people fear is not Russian tanks, it is Russia gaining a lot of influence by making backroom deals, promoting and financially supporting certain political parties and individual politicians whose ideas are useful to them, buying up shares in energy companies, either directly or by proxy individuals (who do not have to be Russians themselves, there are a lot of people who got rich due to having the right connections and they often want to preserve those connections) and gaining cultural influence. Finlandization is often a good enough substitute for the actual conquest. I am not an expert in geopolitics or international relations, but it is my impression that while Crimea does have strategic importance to Russia due its warm deepwater ports, it is harder to make such case for Donbas/Donbass or South Ossetia (or Abkhazia, or Transistria). It is my impression that in these cases it is not necessarily just the territory itself that is important to Russia, but the fact that having disputed territories may make it significantly more difficult for those countries to join NATO and EU, and, that by waging these small scale wars Russia demonstrates ability and willingness to protect their interests, thus sending a signal to many people that Russia is a powerful country and therefore siding with their interests in a domestic politics of their respective countries and trying to establish connections with them is potentially useful. For example, by negotiating with each country individually, Russia is able to extract higher prices for its natural gas than they would be able if EU countries coordinated with each other and negotiated as one bloc. In addition to that, because of these large profit margins, Russia is able to selectively make discounts for some countries in exchange for various things that they want, for example, naval facilities. Thus it is in Russia’s interest to try to weaken the EU, therefore they support various anti-EU parties, politicians (both right wing and (probably) left wing) and people who are influential in politics without themselves being politicians in various ways. However, I predict that it would be much more difficult to attract such allies if Russia would give in to Western demands and remove their troops from regions such as Donbas, because it would be interpreted as a sign of weakness, therefore Russia would not be thought of as worth siding with. Even though these anti-EU parties would probably still be anti-EU, they would no longer necessarily be against, e.g. sanctions against Russia. Perhaps even more importantly, there are a lot of influential people in Eastern Europe and Central Asia who find it useful to join whichever side is more powerful and a sign of Russia’s weakness would make the option of seeking closer relations with the West more attractive, thus reducing Russia’s influence even further.
To sum up, in my layman’s view, I do not think that Russia is hungry for more territory, but it is probably hungry for more power and influence over decision making in other countries (because it is a useful thing to have), which can be acquired by other means than conquest. I conjecture that the present situation in Donbas is probably not because Russia desires to annex the Donets Basin, but perhaps because giving in would send a signal that Russia is not strong enough and/or not willing to protect its own interests (let alone interests of their allies), therefore not worth siding with.