Hi Kaspars,
Thank you for getting back on this.
Yes, offices are in different locations. They have Internet through Fiber, Wireless and sometimes DSL and all with dynamic IP (ISP DHCP), so even I hosted a WireGuard bounce server – whatever this means :D – it will still don’t have a Static/Public IP. About the port part, this I need to check with the ISP at that branch. But I am using WG with some commercial VPN providers and it’s working fine (I don’t know if this can relate in any way).