I’ve never used CasaOS, so I can’t help you with that, but I run NetBird for remote access to my homelab. What you’re describing sounds to me like an issue I used to have with Tailscale.

I think NetBird might be trying to route your traffic through a STUN/TURN server to get around a NAT or firewall. A NAT (in case you haven’t heard of it) is a sort of “mapping” from one IPv4 address to many IPv4 addresses. Its used to "make more "addresses, otherwise we would have run out decades ago. (this is a simplification, its actually much more complicated)

The first thing to check here is: Are you behind a CG-NAT? (there’s probably some websites to check this)

If yes, then there is little you can do without setting up a VPS to get around it.

If that’s not it, then you’ll have to figure out how CasaOS handles networking internally. Your services might be behind a NAT inside.

As for ressources/information, I mostly stuck to the official docs.

Well, if its unbreakable, then its either snake oil, or some variation on the one-time-pad (really depends on your definition of unbreakable).

But having read the article, this is definetly snake oil.

Yes, TinyCore-Core comes without a GUI (like the commenter above said, headless). When they say 28 MB RAM, that might even be overestimating it a bit. All of TinyCore-Core fits into just 17 MB. Of course that goes up if you need to install things, and I don’t know if it comes with an ssh-Server out-of-the-box. So for a proper server setup, 28 MB sounds pretty reasonable.

http://tinycorelinux.net/

It blows my mind, that there is an entire Linux Distro, that fits into a modern processor’s cache. Who needs RAM anyways? (unfortunately, because of how cache works, we can’t actually use it without RAM)

If you run your services off of a homelab rack that dims the lights whenever you power it on

If you are in this situation, then you definetly should get some more power, or at least a UPS to make sure you don’t trip a breaker.