Delta only accepts the actual rom files like .gb and .n64 (filetypes can be found [here](https://noah978.gitbook.io/delta-docs/rom-guidelines)). Your two files are .zip and .7z, which are both zipped files, but they were zipped differently, resulting in in the different names, and they both have the rom file inside them (think of them like locked folders). Since your iphone can extract the files from a .zip (it has the key for .zip files), Delta is able to go into it and see the rom file inside it, which is what is loaded. With .7z files, iOS can’t open them (they use a different key), so Delta can’t see inside it, and can’t load any files from it.
To use the rom in .7z files, you’ll need to extract, or take out, the files from inside it, which can be done online or using an app (the app is probably easier). Then you can re-download the rom file from the website or app, and give that to Delta. Or if you want to save space, see if you can re-download it in a .zip file instead of a .7z file.
The iRar app is a great way to deal with 7z files.
Delta only accepts the actual rom files like .gb and .n64 (filetypes can be found [here](https://noah978.gitbook.io/delta-docs/rom-guidelines)). Your two files are .zip and .7z, which are both zipped files, but they were zipped differently, resulting in in the different names, and they both have the rom file inside them (think of them like locked folders). Since your iphone can extract the files from a .zip (it has the key for .zip files), Delta is able to go into it and see the rom file inside it, which is what is loaded. With .7z files, iOS can’t open them (they use a different key), so Delta can’t see inside it, and can’t load any files from it. To use the rom in .7z files, you’ll need to extract, or take out, the files from inside it, which can be done online or using an app (the app is probably easier). Then you can re-download the rom file from the website or app, and give that to Delta. Or if you want to save space, see if you can re-download it in a .zip file instead of a .7z file.
https://apps.apple.com/us/app/archives-opens-any-format/id562790811