Hi all, looking for some feedback on this hand. Day 2 of 1500 6 Max NL at WSOP. Hero is slightly below average chips with 75 or so remaining. Blinds are 2000/4000 500. Hero is around 125000 chips. UTG +1. Villains of note Button has 250000 tough Lag, playing many pots preflop. Very sticky on the river. Big blind has 300000 has gone on a huge heater. 2 outered 2 people to stay in. Similar to Button style wise, but has shown 2 semi bluffs which got there in huge pots for all his chips. Hero's image likely more TAG, no bluffs shown. I am an amateur, and make it well known I am, which often goes to my benefit.

Hero dealt KsJc UTG +1, Raises to 8500, button calls, Big blind calls. Pot 30500.

Flop Kc 7s 4s. Hero bets 21000. Bigger sizing I know, perhaps too big retrospectively. Button calls. Big blind raises to 55000.

Hero?

Thanks in advance.