I think people are underselling just how cutting down a 162 game season into one series can really tilt the playing field in a team like Detroit's favor
Are they well built? Not really. Their rotation outside of Skubal is hilariously bad, their lineup is almost all sub 100+ OPS outside of Reily Greene and Parker Meadows (who only played 82 games)
What they do have however, is a legitimate stud ace pitcher said Skubal. He's been so good Detroit can essentially just pencil in his starts as wins. When you know you have two of four games won before they even start, that allows you to stretch out your bullpen in the other games. Which in turn also charges what is essentially a feedback loop. Detroit is sending guys out that most teams probably barely have any data on these guys. Like how often do you see the same relievers in the regular season? If you're a division rival like Cleveland then probably more than most. But even then their offense has been shut out twice in that series.
It's a perfect storm of circumstance, dumb luck and some pretty well played tactics by AJ Hinch to make this work. I think they go to the World Series if they beat Cleveland. New York's offense once again has all but disappeared because as it turns out, Aaron Judge and Juan Soto can't go 4-4 every night and drag it to relevance kicking and screaming.