My install of OperaGX wasn't working. It was a complete black screen with no way to interact with it. I uninstalled & reinstalled it.
When I logged into my account & tried to sync everything, all my data was disappearing before my eyes.
When I logged into the sync screen I saw the count for the passwords, bookmarks etc reducing to zero.
They were all being deleted while I was accessing my sync data. I didn't authorise for any of the data to be deleted.