Repeating groups are exactly how you would mimic the functionality on Zoom’s marketplace pages.
The left hand list of categories would be modeled by having a repeating group that displays the names of your marketplace categories. The grouping of individual apps on the right would be modeled by having a repeating group that displays the apps that are associated with that selected category.
This is all so core to Bubble (and to application design in general) that I’m going to point you first to Bubble’s tutorial lessons. Understanding those, a video like this one:
… will help you understand how to build the left menu that allows selection of a category. At that point, it should be clear(ish) to you how to build the right one.
You might also watch the series of videos here, which show me building the core of something that’s like a store. And, though I don’t build a full-on cart (until further down in the thread), watching these will help you understand how you use repeating groups in this way:
Note: while these demos are related to my List Shifter Karma-Ware plugin, what you see me do is just core Bubble stuff and is entirely applicable to your situation.
More to the point: You don’t build a bunch of states that represent categories. The categories are just Things in a list. A Repeating Group can be used to visualize the categories and present a selection mechanism to the user.
Having a selected Category, you now use that Category as a search (or filter) criteria on your list of apps.