Ah, okay I understand. I also asked myself about udp or tcp or both is the better way to go. As the whole video traffic is going through the turn server, I actually would expect tcp to be the better way, because It’s about keeping the connection up. For stun server, which just gives the internal ip information to enable p2p, I would e.g. expect udp as the right protocol. But as the guide uses udp also for turn and this also works, I just leave it there for the moment.
I also can’t get the spreed app running, because there is some error when I try to adjust the TURN server protocols: Spreed app issue with setting "turnServerProtocols"
There seems to be a problem with writing the setting to the database. Did you check if all the values you give in nc admin panel (for spreed app) remain there after page reload? For me (at least for the protocols) this does not work, even that is says “saved” after I change. Maybe the problems are related.