Failed to Connect Mikrotik to Unifi Dream Machine-Special edition UDM-SE Router

RouterOS Beginner Basics
1

I have 2 stations which are over 100kms away.
Headquarter (HQ) - Mikrotik Router
Fort Branch - UDM-SE Router

They both got wan/ Public IPs. we have failed to configure traffic / packets to flow between sites.

How do you configure them with GRE tunnels between UDM-SE and Mikrotik?

2

The GRE tunneling should be between the Mikrotik and UDM-SE routers

3

Unifi has wireguard, I would focus on that for connecting the two devices securely and for remote management of both devices via Wireguard.

4

Have y*ou practically made a connection of these two routers Mikrotik and UDM-SE and you succeeded?