So here's the deal: Dark Phoenix wrapped production way back in October 2017, and was originally meant to open in November 2018 but blew past that date when extensive reshoots were ordered. Those reshoots apparently altered things considerably, including a change in the setting of the final battle...
"the filmmakers decided to revamp the look of Phoenix in post (more “cosmic” and less “flamy,” according to the director) and shoot a new third act (instead of taking place in space, the climax finds all the X-Men kidnapped and on board a military train)."
If you've gotten a look at the train scene in the trailers there's nothing really wrong with it, but that's a very significant change to make so late in the game. What's the storyline reason for something like that? Maybe the thinking is to humanize this fight by placing people in Jean's destructive path, but they probably could've accomplished that in a different way. A train fight sounds so anti-climactic.
Anyway, Dark Phoenix opens on June 7th and maybe it'll turn out great.