WireGuard is a low-overhead lightweight VPN solution which is basically a mesh p2p solution, but can be configured with a central peer which routes traffic to other peers (or road-warriors)
here you can find some wireguard tricks & infos to make your life easier

official site:
https://www.wireguard.com/
android utils:
https://f-droid.org/it/packages/com.zaneschepke.wireguardautotunnel/
https://f-droid.org/it/packages/de.marionoll.wgautoconnect/

also, TailScale is a valid wireguard-based cloud alternative, which has some closed-source components:
https://tailscale.com/
https://github.com/tailscale/tailscale
https://f-droid.org/it/packages/com.tailscale.ipn/

headscale is a pure floss implementation of tailscale: https://github.com/juanfont/headscale