Ios is trash (I mean their mobile phones), not the blockchain app, maybe blockchain app is not just running well on your Ios device, therefore buy android phone instead, you'll find the conveniency you're searching, because lots of btc wallet or altcoin wallets are supported by Android.
I'm not an android promoter, but I just don't find my freedom on Ios devices, and too expensive, like what's so unique about it?
Their entire ecossystem? The OS and their products are way better polished than any Android phone. Also the fact that they still support updates for phones 4-5 years ago, while android phones usually get updates for 1-2 years and then you need to use shady roms and root your phone (less overral security).
Yes, iPhones have several downsides, but I was an Android evangelist before and now I'm full iOS (I even have an Apple Watch + Airpods, which makes the entire combination IPhone + watch + earphones perfect).
But that's just my opinion (as so is yours).
And if OP is asking for an iOS wallet, you suggest him an wallet and not tell him "change your phone".
A cool article I found about BlueWallet:
https://bitcoinmagazine.com/articles/bluewallet-to-integrate-bitcoin-lightning-trading-via-hodl-hodl