In my experience the whole DVB driver situation on Linux is really messed up. Seems to be partly because of difficult communication with the linux kernel maintainers and partly because of lazyness of hardware manufacturers (they don’t care). Another problem is that DVB really runs out of favor. It is not “cool anymore” as everyone uses streaming services nowadays and so less and less “spare time developers” still care about “TV”. This even seems to be visible in less and less DVB hardware still developed.
I would just give up on the idea to still run a tuner directly on a PC. Get yourself a “SAT>IP” tuner, add it to your network and stream your TV programs over your home network.
Edit: It is even possible to set up your own Sat>IP server with “minisatip”. So you could get a mini PC, plug the tuner(s) you already have, only care about getting them working there and bury this dedicated TV streaming server somewhere in the house.