Does anyone from Mojang even read these? It's been two weeks and no contact! I hate companies that don't offer live phone support. At least respond to the online support if that is the way you are going to go!
Today I tried starting Minecraft using my (parents) account as well as my older son's account. The parents account loaded Minecraft super quickly. Of note I have no worlds or downloaded content for Minecraft on the parents account. Then I switched to my older son's account. His loaded more slowly but what I would consider the "normal slow" for Minecraft. He does have a number of worlds and downloaded content. Finally I tried my youngest son's account, the one having the issues. He also has a number of worlds and downloaded skins/mods (I have tried disabling all skins/mods). Once again the Mojang loading screen with the grey bars took ~5 minutes to load. Then upon selecting the world he wants to play in again the "generating world" loading takes an extended period of time, approximately 12-15 minutes.
I am not sure if this is related but I noticed when looking at cloud saves that the parents and older son's accounts were saved. The younger son's account seemed to be stuck in needing a save. I went ahead and had it do a current save.
We are also seeing the "error loading character 1" (repeated for 2,3,4) when starting the game in the problem account.
Still having this issue as of 11/30/20.