I just rebooted after creating the file and it worked.
This is another solution:
Now, 6.14.0-2 is current version so not a downgrade but you could rename them something like .bak and reinstall kwallet or just rename and try a reboot if they are recreated.
I think there are a different cases floating around, those who didn’t downgrade from 6.14.0-1 to 6.13.0-1 (like me, I didn’t notice I had a problem until after the next release).
I don’t know if someone who did downgrade and then upgrade have issues.
Then some different stranger problems like yours, someone else who had mayor issues after upgrading in GUI and had some files mismatch.
EDIT: I realized you need your passwords, removing folder ~/.local/share/kwalletd would remove your passwords, the passwords are stored in kwallet.kwl file in that folder. So maybe not go that route.
In theory you should be able to import your kwl file to a new wallet but I am out on deep water.