This is interesting. So these have the “non BT 2.4Ghz” protocol that you generally find in the huge wireless gaming headset?
Yes, exactly.
Actually "Gaming" was exactly the keyword that finally made me find these things. Looking for "normal" headsets/in-ears you can find some that also claim to be optimized for conferences and of course they also claim "low latency", but looking deeper the best they typically have are aptX-LL or something, which does shit when in duplex mode (unless yours and their bluetooth stack allow some hackery like Faststream). But the gaming-optimized ones typically offer real low latency.
Downside of in-ears is obviously the battery lifetime. I think I need to quick-charge them every 3h. But it's not often a problem, since most of the time I put them in their charging box during a short (5 minutes or so) break which is enough to boost them long enough that I don't even notice the battery through out a longer session. Upside - which I wanted them for is - that I don't have a large headset covering my ears and pressing on my head.