My Matter over Thread stuff keeps occasionally falling over in Home Assistant and becoming unavailable, probably a router issue as I’m using a homepod mini but still endlessly frustrating.

I’m using ZBT-2 with HAOS on RPi 4 4GB. It’s rock solid in a crowded apartment complex. Devices are 90% IKEA and 10% Aqara. Definitely try that antenna and don’t connect additional border routers. Let HA own everything.