I need to have more photos to create Memories on iPhone

I'm using iPhone 11 Pro Max with the latest iOS. I used to create some Memories for my family and friends yearly with their pictures and there was no limited number of photos to create them but after I upgraded iOS, I can't create Memories more than 500 photos through Album. Also when I try to create Memories through People album with more than 80 photos, it's not even working properly. This is such a huge bug. I'm not sure why Apple made limitation on creating Memories but it has to be fixed.

+) Also, I used to be able to choose title, main picture of Memories, and audio volume of each video, but all of them has gone. Why did you remove them? Upgrading iOS has to be making it better not worse : /