Human beings in the 1970s were able to throw a hefty chunk of metal (eventually) out of the Solar System, so interstellar travel doesn’t require any future breakthroughs (though such breakthroughs would make it easier). See Project Orion) for an early look at the feasibility of interstellar travel without space elevators, uploading, nanotechnology, or AI.
I fail to see how your second sentence follows from your first. What do you mean by relatively trivial?
Human beings in the 1970s were able to throw a hefty chunk of metal (eventually) out of the Solar System, so interstellar travel doesn’t require any future breakthroughs (though such breakthroughs would make it easier). See Project Orion) for an early look at the feasibility of interstellar travel without space elevators, uploading, nanotechnology, or AI.