Please advise us how to pull user history through mac address in watchguard.
There really is no way.
The WG logs do not include MAC addrs - only IP addrs.
You can look at the ARP table to see the IP addr associated with a MAC addr.
You can set up DHCP reservations to always have a specific IP addr associated with a MAC addr. Then you can get user history based on IP addr.
You can have your users authenticate to the firewall, possibly automatically using SSO, and then you can get user history based on user ID.