I’m facing problems with FPS drops and even lag when fighting against large groups of FNIX and Apocalypse machines. I also face the same problems during maximum level FNIX Base Assault and Base Defense missions. I play on the Xbox One S and it bothers me a lot. If you can fix this problem I would be grateful.
Maybe you should go To settings and delete something useless, because I did that one day(ps5 platform). Game was lagging like crazy but after deleting something useless crap that I dont need, it started working Better than before. You should try that too👍