Yeah, post midnight tunnel vision kicked in by the end 
So some additional info:
- I see a lot of mentions of āmanjaro unstable is arch stableā, I guess I believed it too muchā¦
- Polonium git page states āX11 has been briefly tested but is not supported.ā So I thought it should function on a basic level.
Anyway, polonium is installed with kpackagetool6 and I couldnāt figure out how to revert that, so I opted for switching back to stable. In between rsync fixed a dirty flag on the boot drive, but there were no other errors. After reverting to stable I tried to downgrade packages back to their stable versions, but that fails with a big wall of text that starts like this:
error: failed to commit transaction (conflicting files)
kguiaddons5: /usr/bin/kde-geo-uri-handler exists in filesystem (owned by kguiaddons)
kguiaddons5: /usr/share/applications/google-maps-geo-handler.desktop exists in filesystem (owned by kguiaddons)
kguiaddons5: /usr/share/applications/openstreetmap-geo-handler.desktop exists in filesystem (owned by kguiaddons)
kguiaddons5: /usr/share/applications/qwant-maps-geo-handler.desktop exists in filesystem (owned by kguiaddons)
kguiaddons5: /usr/share/applications/wheelmap-geo-handler.desktop exists in filesystem (owned by kguiaddons)
kwallet5: /usr/bin/kwallet-query exists in filesystem (owned by kwallet)
kwallet5: /usr/share/man/man1/kwallet-query.1.gz exists in filesystem (owned by kwallet)
kglobalaccel5: /usr/lib/systemd/user/plasma-kglobalaccel.service exists in filesystem (owned by kglobalacceld)
syntax-highlighting5: /usr/share/org.kde.syntax-highlighting/syntax-bundled/4dos.xml exists in filesystem (owned by syntax-highlighting)
At this point I booted up the system and it works. Its really strange because plasma 6 is active with x11, polonium is working, as is valgrind. Makes me thing something completely unrelated went wrong.
For now Iāll test around if its stable enough, thanks for the help.