I think either way it's just speculation how things will be affected. Like space is big but it's also going to be chaotic af and remember that both galaxies have inner cores containing supermassive black holes and a higher density of stars, as well as both galaxies have satellite galaxies with their own cores that can join in on the chaos. Those black holes have high energy jets that they shoot off perpendicular to their accretion disc, which could get messed with as matter starts coming from all directions instead of generally falling in from the galactic disc.

Currently, the stars in both sets of galaxies have relatively stable stellar orbits and are moving together. The collision will affect those stellar orbits, not just increasing the number of rogue planets flying around out there but also the number of rogue solar systems, including a non-trivial number that will be flung from both galaxies.

No idea what would happen to us if our solar system was one of those. Do we need a galaxy or would it just make the night sky more boring to not be in one?