for linux you can use xterm, or for windows you can use the built in RDP or a 3rd party such as my commented remote administrator; there are countless how-to's on remote desktop protocol stuff out there.... TV is just nice because they have a 3rd party reporting/relay server.
I tried different services and applications, but most of all I personally like TeamViewer. I think this is the most successful, stable and reliable solution for organizing a remote desktop.
teamviewer is paid program (and way too expensive imo)
you can cheese it, but it will notice you using it for professional purpose and kick u off eventually
what a headache
i use:
https://remotedesktopmanager.com/home/download (basic RDP connection no port stuff needed)
free, easy, no license shit
people using teamviewer in 2019 :O
for windows to windows i use remoteutilities you get like up to 10 connections without a licenes and for windows to linux i use tigerVNC. both programs work alright
in linux you have to do some fiddling to get it to work but it dont take to long read the readme.