Kaiet4

And when I put in my username, it shows that it's already registered. It confuses me a lot since it's my own account that it's talking about. 

I'm having the same issue. When I started Minecraft I had Java first, and when the Microsoft migration things happened, I did what was needed. 

I haven't had this issue in the past but as I tried just recently to play Java again, my username isn't registered? I've had the same one for awhile and it shows up in the username bar faint.

My Java username is Kaiet4 and it is associated with my own account. But overall, Java claims that I don't have a username though I've had the game in its edition for longer than its been with Microsoft.

Same issue on my Xbox One Bedrock. It's been a constant issue but seems to change based on the locations of the nether portal.

Before I made a nether portal that placed me in a different part of the world when I exited, and when exited, part of my world wouldn't render. In that part was my house where my original nether portal was located. The only way I've been able to fix the rendering issue (as when as the loading screen issue later) is by exiting the game and reopening it, the good thing is that it still saves all the changes made to my world before exiting. 

After relocating my portal in the nether to connect with the one in the overworld, I started to not be able to load into the world at all, having the dirt block loading screen.

Since before when I loaded through a nether portal that was in a different location, I think that because the chunk that the nether portal is in won't load, it stays stuck on the loading screen indefinitely (Waited an hour to load but wouldn't load in still).