I see the same behavior here on OH 3.3.0M3 - the channel is presented as a trigger channel, so no way to control the light.
The device I use is a Tuya RGB flood light that zigbee2mqtt recognizes as TS0505B, controlling it in the z2m UI is working fine.
The Thing in the code tab looks like this:
UID: mqtt:homeassistant_zigbee2mqtt_5F0xa4c138e6ad342e03:8498e3f762:zigbee2mqtt_5F0xa4c138e6ad342e03
label: Floodlight01 (Sensor, select, Light, Sensor)
thingTypeUID: mqtt:homeassistant_zigbee2mqtt_5F0xa4c138e6ad342e03
configuration:
topics:
- sensor/0xa4c138e6ad342e03/linkquality
- select/0xa4c138e6ad342e03/effect
- light/0xa4c138e6ad342e03/light
- sensor/0xa4c138e6ad342e03/last_seen
basetopic: homeassistant
bridgeUID: mqtt:broker:8498e3f762
Guess I have to link it manually into OH. Or did someone succeed and is willing to share the config?