Where do I begin? I guess saying that using thunderbird or neomux is a huge upgrade. Just the ability to filter or add tags is huge. But I don't know an alternative in iOS which frequently doesn't even update and inline displays pdfs making it easier for scammers

Not the original commenter, but it regularly fails to update emails unless it is restarted. Last 2 major iOS versions have had the same problem for me. That’s a fundamental functionality failure in my book.