Super cool, during covid times I sorta started making a system where you could back2back dj mix with a remote friend, but never really got anywhere. Would love to pick it up again, or know if there have been some new developments in this field? There are some ‘jam together’ type projects but as I recall, these werent really suitable for DJ mixing electronic music (latency wise).

the B2B idea was something i too wanted to implement but ultimately didn't want to look too far ahead and bite off more than I could chew knowing the potential problems as mentioned below by the other commenter with latency, mixing and syncing, interpolation, extrapolation etc.. At that point I just decided to focus on 1 DJ / Producer doing a live set and essentially just live broadcast without any sync issues to handle as it wouldn't matter if the set was delayed. But it would be so cool if that feature could be implemented. I hope one day somebody much smarter than me could work towards some of these features.

Unfortunately, you're usually working against physics and not software, because, as you allude to, playing music together requires near perfect latency (some sources say 10ms as an absolute maximum) that's physically impossible to achieve over a long distance, even if you had a perfect connection.

Yeah right? But there must be some clever tricks, like a 1 bar buffer and only sending timing info and control data over the network mmmmm

Perhaps you're being coy. But, I'm pretty sure people do this. The performers can collaborate in "real time" (still offset from each other in real life) and the other participants (dancers and listeners) only hear finished music at the same time as all the other participants.

The latency is in the audience/performer energy.