I managed to solve it myself.
- Stopped the tailscale app in HA
- Removed the machine from my tailscale account
- Removed all DuckDNS related stuff from HA
see: Switch from DuckDNS to Nabu Casa - Retsarted the tailscale app in HA
- Machine came up with funnel activated in my tailscale account
The rest was a piece of cake.