Fear not, you didn't lose any of your progress (unless you plaid on a realm), all the worlds are saved ~/.minecraft/saves. If you don't want to buy another acc

Fear not, you didn't lose any of your progress (unless you plaid on a realm), all the worlds are saved ~/.minecraft/saves. If you don't want to buy another account you could use one of the many launchers that allow you to play without an account (tlauncher, shiginima...) but your mileage may vary. You could also use multimc but, since it requires an account to download the assets, you'd need to copy around the files in the .minecraft folder used by the official launcher which can be challenging and annoying to do. Edit: I have a similar thing going on with Microsoft too, to migrate the account I need access to the email which I no longer have. I've been opening a ticket every ~3 months for the past ~2 years and they still refuse to switch my email address. Luckily I can still play the game (not for long) since I still have access to the account