Thanks for suggesting remmina, it might be a teamviewer substitute for a couple old relatives PCs. However I have to solve the dynamic IP problem that doensn't exist on teamviewer, so I was attempting to build a string that sends an email with the IP as payload.

Something like this: curl --url 'smtps://smtp.gmail.com:465' --ssl-reqd --mail-from 'xyz remote IP' --mail-rcpt 'myaccount@gmail.com' --upload-file mail.txt --user 'myaccount@gmail.com:pwd'

Where rather than the mail.txt file I can send the public IP of the remote machine, such as the output of "curl ipinfo.io/ip". Unfortunately I couldn't find how to do that. Backquotes also don't work, it wants a file.

The purpose would be to build a "pre-command" one liner that sends me an email with the remote IP as payload every time the remote user accepts an external connection through remmina. The remote users are old relatives with no knowledge about computers, so the simpler (one click) the better.