What I’m reading is that you want site-to-site connectivity. Wireguard + possibly dynamic DNS makes this pretty easy (assuming you can open ports and configure NAT at your sites). Or you could set up some other VPN solution like OpenVPN.

There’s also tailscale (a paid service) for facilitating the wireguard setup, NAT traversal and relaying. headscale is a self hosted solution that aims to provide something similar (but more limited in scope).