Retrofit solution for door opener and video intercom system

Doorbird also has forced cloud.

Yes, I saw that earlier too.
In terms of type, the Goliath 1x Monitor with Fingerprint and RFID would be the most sensible option.
I just don’t yet know how I could forward the fingerprint signal to an electronic door lock instead of an electric door opener.

the one from Somfy can be used both with and without a server

Doorbird also has mandatory cloud usage.

That may be, but the converter should be independent. At least, that’s how I understand it.

It may be, but the converter should be independent. At least that's how I understand it.

And what do you do with the converter without the Doorbird device? The doorbell wants to or must be connected to the internet, otherwise it simply doesn't work.

The converter only converts LAN and power to the 2 wires of the doorbell wire and then back again. So it should work not only for Doorbird but also for any other IP doorbell. In that respect, I can understand the statement.