Sonoff Zigbee bridge with Tasmota over mqtt

Got my sonoff bridge a few weeks ago and decided to flash it yesterday.
All worked fine, devices pair etc…
As I already have a deconz-stick I cannot use the ZHA integration with it anymore as only 1 per instance is allowed.
As I am having some issues reaching certain sensors (and adding more routers simply doesn’t work) I was thinking about adding them through mqtt.
Setoption19 is set to on, but the devices are not auto-discovered.
Perhaps it works different than I expect.

Messages are sent to mqtt, but they are not in Home Assistant format, so would require manual configuration (which I am not a fan of).

Any ideas to try or is this just expected behaviour?

use your deconz-stick with zigbee2mqtt
and your sonoff with ZHA integration

That could work, but the reason I want to add this is that I don’t want to migrate 98 devices to zigbee2miqtt when it;'s working fine (more or less). Besides that I already have zigbee2mqtt running on cc2531 for my curtain controllers as ZHA keeps messing them up., I want to phase out the cc2531