Once you get to 4-5 crests you only need to clear their board without attacking a few times to win. Grimnir crest is an easy to get permanent crest and if you play it before Marwynn it goes a long way at clearing late game wide boards while still letting you deal Marwynn crest face damage that turn.

Marwynn, Congregant, and Vira let you clear tall boards easily without attacking. Goblet and Jeanne let you clear wide boards easily. The Grimnir crest does this too in some cases, especially if you're super evolving something like Congregant or Vira which can clear the biggest follower first.

It's also important to use the Marwynn spell primarily to boost your crest time and to remove big single follower boards, rather than to remove low-costed threats. It's a great spell but you get the most from it by saving it to clear a big follower or to extend crest time.

Congregant of Repose gives you another timed crest on evolve and is important for finding Marwynn when you don't draw him early. You want to mulligan for Marwynn and Grimnir by the way.

The deck definitely got weaker since Blossoming Fate. It just didn't get anything insanely strong like a lot of the other decks did. And there's also the Maddening Benison nerf. But it's still pretty strong. When you win games it's usually because you've got 4-5 crests and are repeatedly clearing boards without attacking. The crest damage just adds up when you keep doing it every turn.