- get a cheapo chinese camera supported by thingino firmware

- install FW.

- extra: install open source NVR like frigade and connect these cameras, preferably over ethernet not wifi.

- extra extra: have a separate VLAN for these cameras.

Now you have a secure isolated system. If you want a remote viewer, you can have a vpn tunnel to your nvr to access it from anywhere in the world.

It’s not a perfect system but way more secure than anything consumer out there