and 3) have nothing to do with 1). If you want to do what you describe, 2) and 3) won’t help you.
You need 1). Now it depends on your equipment, and your willingness to learn and set it up yourself.
If you want it quick and secure, use Tailscale.
If your router has a build in VPN server, it is done simple and fast as well.
If you need to setup a server on your network yourself, you need to learn how to install it safely, and you need to admin it constantly. But you will learn the most from doing it yourself.
I use PiVPN/Wireguard on the same Pi that runs PiHole on my home network. It works perfectly, totally free and open source, and everything runs in-house so I’m 100% certain my data stays private.