So I am having a problem where every time I launch Minecraft via the Minecraft launcher, whether it be normal 1.16.4 or optifine, when I try to load a world, it gets stuck on the "reading world data" screen. This has made the game completely unplayable for me. I have tried reinstalling, etc and nothing has worked

It seems that the launcher itself does not close after launching, as when I go into task manager, and end the launcher task manually, the world will then load. The same is said if I launch Minecraft and it does not launch, I have to end the launcher task manually, and then the game will launch. This doesn't let me keep my currently registered skin, however.

The game is still technically playable, but I do not feel like this is how it is supposed to work, and I do not want to play the game like this. PLEASE any help or advice/fixes would be greatly appreciated!