The issue seems to be that you have explicit configuration foris-controller.ubus=ubus in the UCI. The reForis works only with mqtt bus. The enough fix should be:
uci set foris-controller.ubus=mqtt
uci commit foris-controller
/etc/init.d/foris-controller
The Turris OS 5.3.0 is going to remove the ability to run foris-controller on any other bus than MQTT and thus resolving this issue.
Why installation of reforis-netboot-plugin helped is because it pulled in reforis-remote-devices-plugin and that depends on foris-controller-subordinates-module which works only with MQTT so it forces foris-controller to switch to it. It should be safe to remove netboot once you set MQTT as the foris-controller’s bus or after Turris OS 5.3.0 release.