i was using DLSS Swapper:
this is the content of my folder:
Even tried to remove the Reference.xml, but same result.
I do not remember where I got the CustomSettingsName.xml anymore.
Maybe it is the wrong one?
EDIT: Nevermind. It was the CustomSettingsName.xml alltogether.
Deactivating this and go with the REference.xml alone solved it for me.
Thank you for pointing me at the right direction!