u/Pvaleriano: See above. u/thekrautboy has explained it very clearly!

tl;dr: Tailscale is more scalable to add more devices to it. Headscale is the selfhost option.

Warning: Deep Dive.

Wireguard is device-to-device connection (broadly speaking). Start looking into Overlay VPNS.

Tailscale is the most famous one and can be self hosted.