Mace works better with a target lock synergy.
Tie Fighter is fast, high chance to go first and get TL up which gets Biggs taunting. If you don't, all your squishy ships are vulnerable and you could lose a squishy early.
Umbaran/Fives is Republic, Tanky, Fast with TL that cannot be resisted. You can either put him in starting line up or first reinforcement to do his AOE the moment Biggs is dead.
First Order TIE is fast with TL, but the pilot is hard to farm and recently got fixed.
Bistan U-Wing is also fast, irresistible TL, passive that works with TL, but 2 crew needed.
Vader which you have, will keep all the TL up, and allow Mace to spam his AOE.
Biggs is your tank. Star Up both ship and pilot and give pilot as much gear, skill levels and level 15 mods that you can.
Boba has high chance to TL, AOE all TL that can AB plus another AOE, good to put in starting line up.
Maul is a good reinforcement too when you put up retribution on a remaining tanky ship like Fives or a TL ship like Boba.
Good luck.