Also, video makes it 10-70 ms worse due to frame-buffering and significantly worse codec latency. If you're within 2-3h by car, try ethernet cables and Mumble/"

Also, video makes it 10-70 ms worse due to frame-buffering and significantly worse codec latency. If you're within 2-3h by car, try ethernet cables and Mumble/"Jitsii Meet", the former at a low-latency star point (locally, if you have to) and the latter in P2P mode. 30ms end2end is possible, but 50ms end2end is quite realistic if you have good internet routing. Inside a city even 10ms could be possible, but that'd need some ultra-low-latency software, no Coax/DSL (Ethernet-based FTTH should do), and a kinda-exotic low-latency soundcards, because Opus alone eats 5ms one-way in the restricted-celt-only-low-latency mode. This is basically the delay of sharing a round meeting table for ~20 persons.