This question has already been discussed about with Studio 2021. It happened to me when upgraded from Studio 2019 to 2022. The problem is that C:\Users\yourname\Documents\Studio 2021\Projects is empty and I don't know where project.xml is.
Also, the server list in GruopShare disappeared. These problems never happened while upgrading from previous versions.
Surprisingly, Studio 2019 still works while the instructions of the upgrade warn that it won't.
Thanks in advance,
Dudu Koren