Z2M parallel with another MQTT instance

I run HA on a hw machine Odroid C2, no virtualisation.

I have MQTT addon installed for retrieving data from Solar Assistant (SA being a MQTT broker publishing data locally and HA read the data from that broker).
I had a discussion with somebody that it is not possible to run a second instance of MQTT for retrieving data from another Solar Assistant machine in the network.

I mention I have 20 devices tasmota MQTT clients working properly but this may be a parallel topic.

I want to add Zigbee solution to HA by a HW LAN coordinator.
Currently struggling with ZB-GW03 v1.4 to make it update and working properly (a lot of headaches).
Probably I would have to switch to SLZB06 (Z2M) or M variant (ZHA).

I am pointed to zigbee2mqtt because it seems easier to understand and manage.

Would z2m be able to be integrated in my setup in parallel with MQTT SA setup?
Would you recommend to go on ZHA approach (SLZB06M) because of the MQTT particularities of my setup?

Thank you.