Username won't upload when I log in

When I try to play minecraft through the up to date launcher, it keeps having my username be seen as player and not my username of Greion and makes me have to choose a new username. I can't even choose Greion as my username because it'll say that name has already been taken. I have already tried logging out and logging back in several times and that didn't work. I have also tried uninstalling the launcher and reinstalling the launcher and that didn't work. I have even tried switching microsoft accounts even though I only use this one for minecraft and that didn't work. I'm not sure what else to do. It has even said I need to buy the game again even though I already own it a few times after logging back in. But my modpacks that I've used still are shown despite all of that so I'm not sure what is going on with it.