Stuck at change class lvl 80

Dear all, appreciate that you guys can help me out. I am lvl 106 and I can’t change my class. I am left with 1 condition and that is to achieve lvl 20 and more auto battle. I am at 17/20 and it won’t increase no matter how many lvl I have tried

just manually kill mobs and auto battle level will increase

Yeah just manually attack. Use your AOE skills

Go to small maps (like cramped alley at first area) and just use your aoe skills, will take you a few seconds on manual