You could install OctoPi and use that camera feed. It's a little overkill compared to motioneyeOS since it's originally meant for monitoring and controlling 3D printers, but I've had better luck getting OctoPi to set up a camera feed than motioneyeOS, which was abandoned by the developer years ago.

You could install it on the NUC, plug in a camera, and it should just work. Then use whatever remote access method you want, i.e. tailscale, port forwarding, VPN, etc.

I think it depends on the thickness of the cheeks and thong/string. I have a thicker than average booty for a guy, and I usually just feel thongs rest between my cheeks. If I start doing some crazy stretches or yoga I'm sure it'd get a little closer to the anus as things spread out.

Strings definitely get more up close and personal, but I feel it more on the top of my ass where it meets my back and on my gooch than my anus directly. It definitely goes a little deeper between the cheeks though, but I sure don't feel it rubbing against my anus. The right thong/string should feel like almost wearing nothing.