Caution! read this before try it.

[Maxatma]

"estimated" NSCollectionLayoutSize dimension working bad, as u can see in logs when running CardsViewController. It just adds every estimated width/height as a constraint, which creates conflicts. ( which in my case also leads to a huge freeze)
You can see also https://developer.apple.com/forums/thread/673940

So, I think UICollectionViewCompositionalLayout isn't usable on production projects (unless Apple will fix this).

I hope, this information will help someone.
Thanks for sharing this project and for your work :)