in order for melee to work you have to always melee from the back
if for some reason your meleeing from the front you just have to watch them and look for the knife swing once you see it you can hit them (unless lag) that’s how you melee always jump in between swings also cause there are a few builds which let FT kill predators in melee in sub 3seconds (which is faster than all full combos) where legit the best strat at dealing with melee predators is to stand still or backpedal and let them melee you cause they will die first
this is the way the game is intended to be played i’d recommend just not doing melee ranged is always better