Cool game, but besides the file size being big, it also puts a huge strain on my computer's processing system. My GPU went up to 100% which can actually put your computer in danger of over heating and seems to be common with Unreal games. Fortunately, it is possible to optimize Unreal games (and maybe you already did and this is redundant), but supposedly it's possible to reduce strain by setting your assets to display at lower polys when further away, breaking your world into smaller chunks with level streaming, etc.. This site had a lot of suggestions.
https://leartesstudios.com/blog/10-tips-for-improving-performance-in-unreal-engi...