The scenarios you described sound plausible, but it could also be the other way round:
if there is a constant amount of work to do at house, you can do it 20% faster, so not only you have more energy for the remaining work but also more time;
you could spend some of the extra energy on figuring out how to capture the benefits of your work;
you could spend some of the extra energy on fixing things that were slowing you down;
the drug might make you better at other things, or at least having more energy could create a halo effect.
So I guess the answer is “it depends”, specifically it depends on whether you were bottlenecked by energy.
The scenarios you described sound plausible, but it could also be the other way round:
if there is a constant amount of work to do at house, you can do it 20% faster, so not only you have more energy for the remaining work but also more time;
you could spend some of the extra energy on figuring out how to capture the benefits of your work;
you could spend some of the extra energy on fixing things that were slowing you down;
the drug might make you better at other things, or at least having more energy could create a halo effect.
So I guess the answer is “it depends”, specifically it depends on whether you were bottlenecked by energy.