Ah! I can see problems happening if you do reach those high densities. If an app change was able to fix it somewhat, then it may have still been some configuration problem. Too many people trying to join the same mesh with sub-optimal settings. But, at some point you might indeed get just too much radio interference from different devices trying to communicate at once. Certainly possible!

I just learned about Reticulum, I still have to give it a try!