But you don’t need to use the predefined muxes. As you say way out of date and useless. If you are installing TVH via the Wizard, when you get to the section Add predefined muxes just press the Cancel key. Then go into Muxes section, add the information for the one known working mux manually and TVH will will scan the whole band and add what it finds broadcasting.
If you want to do a manual scan outside of TVH I suggest using dvbv5-scan. It’s a lot more efficient and explained in detail here. It should be available to install from your package repository https://manpages.ubuntu.com/manpages/jammy/man1/dvbv5-scan.1.html
