Remmina doesnt work for you? Or does it suck with multimonitor servers specifically?

Agreed, a lot of camera’s need weird proprietary apps (or cloud connections) to be set up though (or function fully, even offline), thats why I would recommend this. If yours doesnt: great!

And add some Thingino liberated camera’s to it!

Have a look at Thingino. Comes with wireguard built in. No idea about the solar stuff though. Maybe run it off a generic 5V solar solution.

Well look up DHH, main person behind it, and decide for yourself.