Humans (assuming we are still around) will have to watch from another planet: the collision will happen in ~4.5 billion years [1], and Earth will be uninhabitable long before then [2].
That second link I'd read through before, but oh my, you're right there's a number of critical events ahead: an ice age around 50k years from now; in ~300mil years (oh cool never noticed this before), "All the continents on Earth may fuse into a supercontinent"..resulting in another glacial age; in 700 mil years, "The death of most plant life"..
Also realized, there won't be much "fireworks", since apparently the stars are far enough apart that the merging of two galaxies won't cause much collision.
If we can figure out how to solve our political issues and become a eusocial species, we may be able to build some generational starships. In 4.5 billion years we could potentially colonize many of the planets in the habitable zone of stars in the Milky Way.
Sure, it could take millions of years to cross the galaxy, but we could grow exponentially (like lily pads crossing a pond), at least until other limiting factors kick in.
[1] https://en.wikipedia.org/wiki/Andromeda%E2%80%93Milky_Way_co...
[2] https://en.wikipedia.org/wiki/Timeline_of_the_far_future#Fut...