do you happen to have a guide on how to achieve this - I am fairly technical but still configuring Vlans and moving devices there would be good with some step by step instructions.

Are you running Ubiquiti hardware? If so, should be very straight forward (one of the main reasons I went back to Ubiquiti stuff after running my own OPNsense router) https://lazyadmin.nl/home-network/unifi-zone-based-firewall/

P. Sure the camera in question breaks in fun ways. From my observations because it can’t update it’s time, so messing with it a bit leaving to a need to update, downgrade, block from the web again.

But it’s worth trying

depends on your router, but you would want to stick to onvif or rtsp and connect to the camera using some sort of tailscale. Don't fail for installing open source firmware, there is only thingino and openipc, both are hard to install if you are a beginner, even if people say it's easy for technical specialist, it's not