UPDATE:
I have checked the IP settings in my fritzbox and found nothing unusual. Rebooting did not help either.
So I manually added the local IP to all Tuya devices in the config.
I can get 13 out of 15 devices online in OH this way.
At least a temporary solution for me.
The reluctant 2 are the new ceiling lights with the following log message:
2024-12-15 14:17:07.613 [DEBUG] [.internal.local.handlers.TuyaEncoder] - bfb93a120daa586a72s2eb/192.168.178.49:6668: Sending payload B798A70AXYZ
2024-12-15 14:17:07.617 [TRACE] [.internal.local.handlers.TuyaEncoder] - bfb93a120daa586a72s2eb/192.168.178.49:6668: Sending encoded '000055AA0000000XYZ
2024-12-15 14:17:07.622 [DEBUG] [al.local.handlers.TuyaMessageHandler] - bfb93a120daa586a72s2eb/192.168.178.49:6668: Connection established.
2024-12-15 14:17:07.754 [DEBUG] [al.local.handlers.TuyaMessageHandler] - bfb93a120daa586a72s2eb/192.168.178.49:6668: Connection closed.
==> /var/log/openhab/events.log <==
2024-12-15 14:17:07.627 [INFO] [ab.event.ThingStatusInfoChangedEvent] - Thing 'tuya:tuyaDevice:bfb93a120daa586a72s2eb' changed from OFFLINE to ONLINE
2024-12-15 14:17:07.758 [INFO] [ab.event.ThingStatusInfoChangedEvent] - Thing 'tuya:tuyaDevice:bfb93a120daa586a72s2eb' changed from ONLINE to OFFLINE
Does anyone have the same problems, approaches or even solutions?