Due to the expansion of the universe, we're also going to lose access to the rest of the universe in that time.

  Time - Galaxies lost to us forever 
  1 million years ~ 0.02%
  10 million years ~ 0.2%
  100 million years ~ 2%
  1 billion years ~ 20%
  10 billion years ~ 80%
  150 billion years ~ 99.9999997%

That's all assuming we can't "break physics" and nucleate something new, find a tear in our current manifold, etc. Our peon brains are too small to reason about this and any claims that we're stuck are insufficiently computed.

Given our limited sensing capabilities and tiny time sample, I'm skeptical of our current understanding. Claims of current model predictions feel premature.