And, worse, incentivized to require users to use a "coordination server" which helps with the NAT and firewall traversal problem by being something you can reach from outbound-only clients. There's a lot of verbiage there, but the general idea seems to be that Tailscale sits at the middle of this as the means by which machines find each other.

There are other ways to do that.

There are dynamic DNS schemes, so you can give your machine which only has a temporary IP address a permanent name. That's been around for decades, and seems to have a bad reputation.

There are schemes with multiple coordination nodes that know about each other, and published lists of such nodes. The list may be out of date, but as long as the published list has one live node, you can connect and get updated. That's how Kademlia, which underlies Etherium's network and some file sharing systems, works. That's about 20 years old, and sort of has a sketchy reputation.

It's possible to go only halfway, and separate discovery from transmission. Peertube does that. You find a file to stream via ordinary HTTP to a server you find by ordinary web search means. Anybody can set up such a server. The actual streaming, for files wanted by many clients, is distributed, with people currently watching also sending out blocks to other people watching. This scales well, in case your video goes viral. It's not used much, though.

So it's definitely possible to do this without someone in the middle able to cut off your air supply.