Another tool is paperless ngx. Although it is a bit more than just a scanner Programm.

The fact that the ccc uses matrix as their official chat “app” doesn’t imply that it is inherently insecure I would say.

https://github.com/toverainc/willow

They even have a dedicated piece of hardware for it.

Look into vlan.

Basically allows you to have different subnets rubbing on a physical network card.

It is possible what you want to do and not that complicated.

And here is hardware that works with home assistant.

https://heywillow.io/

Thanks, was about to post the same. I have no emotional attachment to signal, but I haven’t seen a real reason why I shouldn’t be using it anymore. At least from a security point of view. It works very reliably for years now and does most of the things i expect from it.