In GameRanger, I get the following warning: "Your internet connection is behind a Port-Restricted Cone NAT Router that may prevent you from connecting to some players in peer-peer games" Can you tell me what the consequences are? I'm using a 3G modem.

This is a real problem. How to live with it. Does the game connect to other people, and they to you? That's what's important.

Added 5 minutes ago

2) GameRanger. The problem is that the game freezes on the connection screen, i.e., after creating a room in GameRanger, the host and client enter it, the host starts the match, the game starts, but after some time, the host sees that "the player has not joined," and the client/player freezes on the first connection screen, with a sandglass cursor.

I won't say anything about Tangle, but GameRanger doesn't always connect on the first try. Usually, when you connect to the host and it doesn't work, there's no point in waiting for the connection to reset; just wait 5-10 seconds, "abort" (or just close the game) and try to connect again. The host waits in the game. Repeat the procedure n times. It usually helps.

If it doesn't help at all, there's another option with Hamachi and TeamViewer. You also need an account for Hamachi. It's simple: one person creates a network in Hamachi, the second connects to it, they launch the game, enter it, and play. If they don't see green open doors (where to connect), they search by IP address, of course, the Hamachi one. And to see it right away, it's best to set the Hamachi network priority to the top; then it will be okay.

Or just install TeamViewer with the VPN option. One person connects to the other, you get the IP addresses, and you enter the game through them. It's also quite simple; there are even screenshots of how to do it, although they are outdated.

Good luck. Try it, and it will work