I have a Linux server in my office building. I want to run a VPN server on there, so I can connect to that from my laptop and connect to the outside world from my office, regardless of where I'm actually located.
I don't have any advanced requirements, I don't need any particular features other than just being able to connect remotely.
So my question is: what is a good, simple, easy to setup, and preferably open source VPN server which I can install and run on a Linux (Ubuntu 20.4) server. So I can then connect to it from my Macbook (macOS 10.15) or other clients from remote locations, and use my office's internet connection to connect to the rest of the world.
In case it matters: the server is my own, I have root access, and I can create a dedicated user account with required privileges if that's necessary to run a VPN server.