Build mode not working. Hard restart needed every time

When I open build mode it'll let me edit things for maybe about a minute or so before I'm no longer able to interact with anything other than return to live mode. Afterwards when I try to exit, regardless if I try to save and exit or just straight exit, it'll keep me on the loading screen indefinitely, eventually causing me to use task manager to close it by force. I've already tried removing all mods and cc, clearing cache, repairing game, restarting my computer, and even completely uninstalling and reinstalling the game. The only changes that I can think of are that I just installed the Dust the Bust Kit (but that didn't seem to have any effect on the issue) or the latest update. With that being said I'm like 80% sure it's the game itself. Please help if you can, this saves really important to me :')