Not able to set up sync via Firefox with my new desktop computer. I now have windows 11 and I can now longer get in.

My internet connection is with Comcast, whom has told their customers that they will no longer be allowing email addresses with their company’s name. To this end I have been trying to move my old email accounts over from them, and I'm facing a lot of problems. However, since I was able to change the email in the Mozilla account today, I may be able to do it now. Also, please update my computer info to windows 11. Educated guesses below are correct.

Thank you V