Game launches, freezes shortly after

Game launches like normal; plays like normal. after a slightly varied amount of time, game freezes completely, doesnt unfreeze. if tabbed out and returned, creates harsh strobing effect switching swiftly between the red mojang logo and a black screen, also affects the cursor (also for some reason it only lets me input 1.21.4, but this seems to happen with vanilla and modded 1.21.1 and 1.21)