I find the Itch App really useful. But it feels like it's designed either for collections of less than 100 games, or for someone who started aggressively curating lists from the get go.

The problem here is that itch.io will sell you dozens/hundreds of games at once, and trying to browse the list of all games is beyond impossible.

I don't know what the solution is, but access to the My Purchases->Bundles from the website in app would be a start (even better if you could use them as a negative filter)