My world is "deleted" from my main computer

Hi.
I have been scratching my head with this one..

I started a new 1.0 world and at one point I rage quit the game which apparently had saved my character but not the world, leaving my character without gear, but no tombstone to recover.

Ok, no biggie. Just recover the backups right? Well recovery failed without really telling me the details. OK, but the files are on my SSD so I'll just overwrite the current world with the .old version.. That was probably not the right thing to do.

I could load into my world and played for several hours, but saving didn't work. So no world progress was recorded. Having mucked about with backups I am now in a state where my 1.0 world does not show up at all. If I "manage worlds" my world shows up as deleted, but I can recover a backup, but this backup won't save and will show up as deleted when I start the game again. Loading into a different, older world that I haven't messed with, that also wouldn't save. (it just soft hangs indefinitely when I try to save).

I have uninstalled Valheim, deleted the "\AppData\LocalLow\IronGate" folder. Removed IronGate/Valheim key from the windows registry and rebooted before reinstalling. My world is still "deleted".

But! Even if I had never played in this world on my laptop, I could still see the world and play and save the world just fine there. The cloud data is good, and works just fine on my laptop!

How do I perform a proper exorcism on my main PC?