We bought a 3 unit Eero 6 mesh WiFi router. From early days we ran into unreliable video problems. Remote users would say our bandwidth was flagged as poor -- despite having a GB fiber connection and, you know, the Eero routers.
I never found any useful diagnostic or testing information, but the fix was to unplug one of the 3 Eero stations. With only 2 devices the video quality was much better. Presumably we have too many devices for the size of our home -- and the software for managing handoffs might not work as well as one would expect.