I haven't played it personally, but Savage Attacker was garbage in 2014 rules, and 2024 didn't change it any, so arguably it's even more garbage now due to power creep. Great Weapon Fighting (GWF), to my amazement, has actually gotten literally worse not even accounting for power creep. It's still better than Savage Attacker once you get a second attack though, due to Savage Attacker's once per turn limitation. And yes, the raised damage floor from GWF does seem to mean less situations where you would want to use Savage Attacker, and lowered gains from using it.

As for how much it's affected, assuming your DM does not allow these feats to apply to Divine Favor (not sure how the 2024 rules feel about this but I believe that was considered the 'official' ruling in 2014), Savage Attacker adds 1.37 average damage to a hit with your maul when you do not have GWF, but only 0.91 average damage to a hit when you do have GWF.
Source: calculated by myself with anydice

P.S. As a fellow maul enjoyer, thank you for your dedication to the superior 2d6 weapon.