Could be the same issue as Debian11 / gvm 22.4: gvmd.service: Can't open PID file /run/gvmd/gvmd.pid (yet?) after start: Operation not permitted but this time for notus-scanner.
Therefore could you try changing the notus-scanner.service file:
- Use
Type=exec
instead ofType=forking
- Add
-f
to theExecStart
line