I switched from a diy cc2531 to a zzh! And I’m not disappointed, I don’t encounter the problems you describe.
For profalux, the support is not linked to the dongle (it’s Zigbee anyway) but to the software. With the debug info, we should be able to add it to zigbee2mqtt.
I almost got a zzh! but it was out of stock, so I got its equivalent https://slae.sh/. Same thing, works great and is very stable. No need to manually flash the key for it to work, it’s plug and play!
I confirm what @VonOx said, it will mainly depend on software compatibility, but the quality of the Zigbee network will also play a role. If you have unexpected disconnections, it’s possibly the key or a faulty sensor.
My Zigbee devices from Ikea are functional but quite finicky for the first pairings.
From experience, I’ve noticed that Aqara devices never use the Zigbee mesh, always connecting directly to the coordinator even if a Hue bulb acting as a relay is right next to it.
(For those wondering, image retrieved from http://:8080, which is the Zigbee2MQTT interface, the project that Gladys uses for Zigbee)
This isn’t entirely true for me, I have quite a few sensors that use my living room outlet and the one in my office, even though most are Xiaomi. But the vast majority use my Zigbee key, also because I didn’t have the outlets at the beginning.
If I’m not mistaken for Aqara, if the sensor has been paired with the coordinator, even if it is closer to a router, it will continue to be connected to the coordinator (source: I don’t remember!).
