Basic understanding question: ZigBee and multiple Hubs multiple integrations?

[native wind]

Currently I am using multiple ZigBee hubs as all manufacturers keep an eye on you to buy their equipment. So I do have A Hue Pro for some lights, a Tahoma / Somfy for shades and shutters, Netatmo for radiator control and now that I am using shelly and Sonoff for temperature sensors and heating control in an attached building, I am installing another Dongle-M.
In near future I am ready to install more equipment in a newly remade part of the building and as there is a little distance and the walls (built in late 1880ies) are thick natural moist stone, I need another set of ZigBee equipment.

Now the Hue Pro will be able to extend range in future, and I think that this will be handled inside the Hue system while HA only gets more and more devices.
But every time I add another ZigBee stick that is known to Sonoff, that integration asks me to migrate sensors to the new hub. And I really don't wanna do that!

Also I found some cheap chinese LED controllers do work perfectly fine with Hue? Even the light patterns match, even they are not calibrated like original Hue hardware?
But I also found units like Tuya M9pro 4-relay, 8 button switch with LCD. This thing registers against the Sonoff Dongle-M and appears in ZHA but then it doesn't give any sensors, switches or settings and it even never sends something that appears in ZHA logs.

And finally, some blog posts show, that I might be able to discover and do my own thing with the Tuya M9pro, if I connect it to ZigBee2MQTT. But I cannot attach the Dongle-M to Z2M as (I guess) it is already bound to ZHA?
So do I need to add another Dongle-M that I then can attach to Z2M?

May be someone has a minute to clear up the mess in my brain on these more basic things of HA and ZB Dongle use? I am really puzzled.

[junior hound]

So... in general you want to run as few separate zigbee networks as possible. consolidating devices to a single coordinator will make your zigbee mesh stronger and reduce interference.

If you find devices that don't work with ZHA, please report them, it probably will be possible to add them. But you could also consider moving all of your devices to zigbee2mqtt instead if you prefer that platform.

zigbee devices connected to different coordinators (or hubs) can't talk directly to each-other, so they can't relay messages for each-other.

if you do want to run multiple separate zigbee networks because your building makes it difficult for one network to reach the entire building, running multiple separate zigbee2mqtt networks (each needs its own zigbee dongle) is probably the best solution.

consider a device like the smlight slzb-06 series, which lets you locate the zigbee dongle in a different place from where you are running ha, connected over the network.