Unfortunately I did not find any solution to get this setup working. Panasonic TVs seem to be limited to rtp streams, but TVH can only stream http.
However I found another solution that works perfectly for me. My goal was to stream satellite TV via network to my Panasonic TV. I got this working by using the minisatip tool (https://github.com/catalinii/minisatip). It's taking the DVB packets from DVB-S, DVB-T or DVB-C tuners and sends them as DVB-IP to your local network (Astra is calling this protocol SAT>>IP). minisatip seems to be working with ATSC tuners as well, however I was not able to test that yet. Other sources are working perfectly.
Once you have started minisatip on a server in your network, start an automatic channel search on your Panasonic TV. Your TV will find the minisat IP server, using it as source for receiving TV signals afterwards. However there is one particular glitch when starting the automatic channel search: even though I selected the correct satellite in my setup, the Panasonic TV is not finding any channels out of the box.
For getting it working I have to specify an existing transponder on the respective satellite in the channel search dialog. An excellent source for information on TV satellites is LyngSat (https://www.lyngsat.com). It does not matter which transponder on your satellite you're specifying, even transponders with encrypted services may be selected. I guess that each transponder sends a comprehensive list of active transponders of the entire satellite and that the Panasonic TV needs to receive this list for finding all the other transponders of the satellite. It's a little bit surprising that this workaround is necessary, since I preselected the Satellite in the channel search dialog.
However, once you entered that transponder information, the rest is working perfectly. The channel search is finding all channels and you're using your remote control to switch between them afterwards, just as you're used to do with other signal sources.
Important: your Panasonic TV and the minisatip have to be in the same subnet since broadcast communication is used for finding the server. I guess that most private networks only constist of a single subnet, so this is not a limitation here. However, if your network constists of multiple networks, you have to help your Panasonic TV to find the minisatip server. You can do this by either starting a second minisatip server in the other subnet, forwarding requests to the first minisatip server, or using a proxy service like
https://github.com/alexte/sat-ip-proxy.