I use zigbee2mqtt and i love it. I have a few different hardware vendors that work like a charme with it.
Unfortunatly there seams to be a limitation regarding devices. I have a CC2531 USB with antenna and actually it works great.
But there are rumors about a 20 device limit which i will hit in the very near furture. The other chipsets recommended by the zipbee2mqtt.io website do not help, because they are not available for months and will not be as far as i can see.
While I don’t have a cc2531, I would guess the device limit is for devices directly connected to it, not a total device limit. With that said, I have a conbee II and 41 devices connected (using deconz).
I’m not a Zigbee expert but my understanding is that the “20 device limit” means 20 direct device-to-coordinator connections. If you have devices that connect to the coordinator via another device (i.e. it’s serving as a repeater) then that connection is not included in the “20 device limit”. In other words, you can have indirect connections beyond the 20 direct connections.
Of course, at some point the total number of direct and indirect connections will exceed the coordinator’s capacity to handle peak traffic levels. Also, if all of your devices must have direct connections (because none can act as a repeater) then you more likely to be constrained by the 20 device limit.
Well that is helpful to know. I thought it was an “all over” limit. Most of my devices a connected by routers (40 % direct, rest by routers like plugs, lamps) therefor this takes the pressure out.