That PP will be stopped by the blueline alone.
Honestly, we might win a series or two, but we won't go far without PP. No one did that in history.
Well, if our PP continues to achieve a 6ish% success rate, we for sure aren't going all the way, but I did look into previous Cup winners, dating back to the 2009-2010 season and found that a few of them won despite their PP woes.
For instance, Bruins in 2011 won had the 14th ranked PP in the playoffs with a 11.4 PP%. Kings in 2012 had the 12th ranked PP with a 12.8% success rate. The Hawks in 2013 had the 13th ranked PP with a 11.4 PP%. More recently, the Blues won in 2019 with the 12th ranked PP, although there PP% wasn't completely horrendous at 16.3% (interestingly their PK% was terrible also at only 75.4%).
So, overall, teams with bad powerplays have won before, but the way our PP was operating the last while, it still has to improve a lot to match those teams' levels. With that said, if we can continue our dominant 5v5 play, and get our PP% to merely 15% or so, I think we'll do extremely well.