I use wireguard. One network is behind cgnat so i just get that client to connect outbound to the other client to initiate the tunnel (instead of trying to connect to IT) and it works just fine.

I did try tailscale once upon a time but it was so clunky and confusing for me…i just wanted to simply access my entire networks remotely without any overhead

Stupid question.

Does this apply to what you write and upload on the Arduino IDE to your boards? Or just whatever you publish on their website/ cloud?

Is it worth stating which companies own which vpns? I saw a TIL that mentions a select few companies own most VPNs