What is one of the main questions teams are always asking? As you mentioned, how can we gain an edge to win in the postseason. If teams are asking this question, you can bet the analysts are working hard to answer this question.
The very beloved stat geeks have studied this from every possible angle imaginable, including but not limited to, who's hotter, momentum (which doesn't exist from the predictive standpoint), 2nd half records, September records, September 15-30 records, records against winning teams, experienced players versus rookies, pitching, starting pitching, having an ace, relief pitching, closers, defense, OPS, HRs, speed, the ability to play small ball, defense, and payroll. They have found no significant correlation between anything and postseason wins. Nothing correlates to winning in the postseason.
Because of this, teams are better off building to win in the regular season rather than trying to build to win in the postseason. There is no secret formula for the latter.