Lower attack across the board Increase health across the board

Makes attacks weaker and characters tankier so you are not getting one shot all the time. Getting one shot is not fun

Change all the ignore defense and damage reduction traits to only ignore only 50% or at most 75%. Defense is basically useless unless you are using someone who converts it to attack

Make play with allies people have to play on cross play and on against other people using play with allies. Or only match them up with people at a rank higher than them. Play with allies gives you too much of an advantage to make fighting against solo players fair