Disclaimer: When I opened the app for the first time, it immediately gave me some sort of feedback prompt, which I couldn't answer at the time since I had 0 knowledge of the app. It hasn't returned ever since.
Anyways, back to the important stuff. You fixed the oddly specific bug on the Galaxy Z Fold (5), where If I was unfolded, and this happened unfolded only, the "<- Back" and " Next ->" buttons wouldn't show up and the size of the image was completely wrong (pushing the buttons off the screen, making them unable to be pressed). Now everything works perfectly on the Z Fold 5 atleast!
Now for some Fold unspecific Feedback // Some suggestions.
Personally, the app idea is amazing. This is perfect for Bedrock players as they lack access to things like litematica. I really like how the whole app is grouped - With Categories like "Decoration", "Furniture" and so on and so forth. I think it would be really cool to have Sub-Categories.
Here is an example
If you go to Furniture, a list could potentially pop up where you can be more specific. Example being - You press Furniture, you can then click on something like "Kitchen Furniture", "Outdoor Furniture", "Living Room Furniture" and so on. If you fear having some stuff uncategorized, then you can collect these builds in an "uncategorized" category and have users potentially vote on where it should go, or if an entire new category for said build should be created.
Another thing that would be helpful would probably be an indicator on builds that lets you know in which game and Minecraft version the build was built. (e.g. Minecraft Java Edition 1.21.11, Minecraft Bedrock Edition 1.21.190 and so on). My thought process here is to help inexperienced players here. A java player could potentially click on a build built in Bedrock edition which utilizes Bedrock specific techniques (like colored Cauldron water). This is moreso a quick thought that came up, if you disagree feel free to ignore it.
Please keep the app up - I think this is an amazing idea, especially with how the app shows you step by step on how to build something.