There's Unstoppable wallet which is open source, I have tried the Android version but never the iOS one:
https://unstoppable.money/Unstoppable wallet should just be for altcoins, it is not having many other features that reputed open source wallet have. It deos not have RBF and coin control. Bluewallet is still one of the best choice for iOS.
Apart from Bluewallet which I believe is an open source bitcoin wallet on iOS, there is Bither, BitPay Wallet and Edge Wallet. Edge also supports other crypto assets besides bitcoin
This wallets do not have some of the features that Bluewallet has. I can not even recommend these wallets. Almost all bitcoin wallets that have excellent features are not supporting altcoins.
Unstoppable Wallet has Blockchain settings that can be more private by selecting the From Blockchain option, although the API option is recommended. However, the impact is that when opening the wallet, it takes longer for the synchronization process.
The delayed synching occur when you have just created or imported the wallet.