If there are no good cards to play for a long time, my stack will get smaller and smaller. If my stack is below 20 big blinds, I change my style of play. When all the players in front of me have folded, I also play worse hands to bluff. Most players play too tight in the bubble. You can take advantage of that with an open raise. And even if someone calls your raise, you have a good chance of stealing the pot with a c-bet, as most players play fit or fold. They watch the flop and fold to a bet if they don't hit anything. Only if an opponent 3-bets you preflop I would fold with bluff hands. For me, bluff hands for an open raise are K7s-K2s, A5o-A2o, K8o-K4o, QTo. Of course, you have to respond to the way your opponents play. If many opponents 3-bet I would rather open push, so put everything in right away. If your opponents often fold to a raise, I would rather try an open raise.