tried a couple of times but after deleting manually the 3 folder paths in the about section
opera://about/
C:\Program Files\Opera GX
C:\Users(your username)\AppData\Roaming\Opera Software\Opera GX Stable
C:\Users(your username)\AppData\Local\Opera Software\Opera GX Stable
downloads are from here
https://get.opera.com/ftp/pub/opera_gx/
then trying all the 95 versions (none worked)
but the 94 worked then after updating to latest version it still works ... sync is back
this is the one that worked for me (just make sure u have the right version (x64 or not))
https://get.opera.com/ftp/pub/opera_gx/94.0.4606.96/
then select win or mac (but i guess its win users getting this problem)
Opera_GX_94.0.4606.96_Setup.exe
or
Opera_GX_94.0.4606.96_Setup_x64.exe
hope it helps for others ... but i think the key was deleting manually otherwise i would encounter errors uninstalling
good luck
PS: if you wanna save time prepare a copy paste of the links and account and your password cuz i think i tried alot of times