"These plug-ins from github are out of the question, because I don't even know how to run them and I'm not always at home, so that the server (my computer) is always on and watching the sites."
You are asking on "Selfhosted" for an alternative solution to a free selfhosted app, because you are too lazy for "Selfhosting". Wow.
Haha, for my parents it's better to change an unvisible setting in the router, instead of placing a raspberry pi in their network or installing WireGuard on every device. They are paranoid with any software that must be installed :D