These projects really need to consider plain TCP connections. It's a deal breaker for me.
My company installs ngrok on our embedded devices. When there is an issue, they connect it to the internet, type a keystroke, and I'm in.
You can also use ngrok1, which you can host yourself. It's got the features you'd need. This would get around firewalls.
Disclaimer: I work for gravitational but not on teleport.
This has saved me and my customers so many times.