Hi,
I can understand your frustrations with a PostgeSQL update from an old version to a newer one. This seems to be no easy task sometimes. It seems to be a generic issue with PostgeSQL and is not really an issue with our usage of PostgreSQL and gvmd.
Some of our version updates - for example from 21.4 to 22.4 - database structure changes need to be applied. You can run these updates by calling the command gvmd --migrate. So the db update as SQL plaint text export and import via pg_dump should work (assuming you are using the same install prefix) if you stop the gvmd service, run a gvmd --migrate as the gvm user and afterwards re-start the gvmd service.
Just a reminder/hint this is exactly the difference between an open source software that’s free and an enterprise product with support which you are paying for. You need to invest time to care about (database) updates by yourself on your specific platform with your specific update timeline.