
90 seconds does not equal 30 min


The auto-abort is how many seconds you have to make the first move. This is done, so that Player 1 abandoning the game doesn't result in Player 2 having to sit there and wait a full 30 minutes to win the game on time.
Once you get a few moves into the game, then the auto-abort timer won't give you so little time.
https://support.chess.com/article/338-how-does-game-abandonment-work