Sign in to reach your computer from anywhere.
Tip: on your computer run ngrok-like info to get a link that signs you in with one tap.
ngrok-like info
Start the tunnel on it, for example run startvnc. This page checks every few seconds and the card appears here by itself.
startvnc
This page is not using HTTPS, so your key and screen are not encrypted on the way. Use the https:// address if you have one.
Enter the VNC login of that computer (set in its wayvnc config).
Text you type here is copied into the computer's clipboard. Then paste it there as usual.