Played around today with integrating my TaHoma Switch into Hubitat so I can control my RTS blinds using the rule engine in Hubitat as the TaHoma Switch is quite limited.
This uses the new Developer Mode feature of TaHoma Switch. All Somfy devices are controlled via the LAN. Only the initial auth between Hubitat and the TaHoma Switch needs to go over the internet. There's also a periodic security token refresh that needs internet access.
It only works with RTS blinds at present as that's all I have registered with my TaHoma Switch. It should be easy enough to add more device types now the core integration is in place.