World stuck on Building Terrain after entering/exiting Nether

I was playing in my Survival w/cheats world, doing a raid. Wave 3 (I think). All but one Pillager dead. I look all over the place for 10-20 minutes. Can't find it. I go into Creative mode. Search 10 more minutes. Still nowhere to be seen. I think to myself, "Maybe it went through my Nether portal." I go into the portal. Game stops loading entirely and freezes on the Building Terrain screen. Happened the other day, and was fixed then by closing and reopening Minecraft. I try that. I open up the world again, and it does the same thing, but trying to take me back to the Overworld. Then it crashed.