Wasnt there almost the exact same thread, except for bladesingers? Stop giving out powerful magic items and rolling for stats if you dont know how to run a montyhaul campaign. If the pallys too strong buff the othe other players and increase the challenges. Use AOEs that still do half damage on a succeed. Have mobs use the help option, alot of mobtypes have pack tactics which give advantage. Ac is everything in 5th, especially as your levels rise.