I was thinking of the following
Backlash Cantrip 1
Raise a hazy film of retaliating force.
Cantrip Concentrate Force
Cast: [1A] to [3A]; Traditions: Arcane, Divine, Occult
Duration: 1 min
[1A] 1 Retaliation; [2A] 2 Retaliation; [3A] 3 Retaliation
Deal 1d4 Force dmg to the first # creatures that deal dmg to you with Melee or Unarmed Strikes.
When last retaliation is used, then spell ends and can’t cast it again for 10 min.
Heightened (+1): +d4 Force.
This is a mix of the above plus the Shield spell