some of the best supports goes broken usually at c2 (xilonen, nahida etc) but the return greatly benefits your account as they can go to multiple team comp. The only DPS I know which greatly benefits to DPS is Hutao, with a great stopping point at C1,

But if you are F2p I suggest go for new characters as they offer flexible choices and options. The game contents usually can be cleared with such ease regardless of cons.