I have a ZEXMTE 5.4 USB Bluetooth Adapter and a SONOFF Zigbee dongle which both work great except my rather large house needs better range. I have my system located as best as possible and seperated my antenna’s with USB dock extenders but occasionally some of the distant devices would disconnect/reconnect repeatedly and some others slow to respond even with repeaters in the system.
I picked up a pair of these 8dBi high gain replacement antenna’s and it was enough difference to tighten up both Bluetooth and Zigbee networks. Not a ton of difference but enough to really stabilize things. For $9 a pair I figured it was worth a try and it was. Your mileage may vary but for me it was a winner.
Sure I’m using the one at the link below. As stated the antenna’s weren’t a huge improvement for me but were enough to really stabilize everything I had a couple Zigbee devices that would drop occasionally as well as a couple Bluetooth devices and they have not dropped once since the change. The BT adapter was recognized immediately by HA.