Hi there! I understand that you're having trouble finding the Omega Flowey app in the App Store on your iPhone. Let's see if we can figure this out together.

First, can you tell me what search term you're using in the App Store? Sometimes, using the exact app name or related keywords helps. Also, are you searching in your local region's App Store or a different country's store? Region restrictions can sometimes affect availability.

Since you're on iOS 15.8.4, the app should be compatible if it's available. Notably, Omega Flowey is listed on the App Store in the UK region, so if you're outside that region, that might explain the difficulty2.

Here's what I'd suggest as next steps:

1. Open the App Store and directly tap this link from your iPhone: Omega Flowey on the App Store. This should take you straight to the app page if accessible in your region.

2. If that doesn't work, check your Apple ID's region settings. Sometimes apps are restricted by country, and changing your Apple ID's region temporarily can allow you to download region-locked apps.

3. Alternatively, if the app has been removed from your region's store or is not available anymore, that could explain the issue. Some fan-made games occasionally get delisted or restricted.

Could you try opening that link and let me know if it takes you to the app page? Also, if you're comfortable sharing, your current App Store region would help me guide you better.

Looking forward to helping you get this sorted!