As far as I know, you need to compile down the codebase to an Xcode project before you can build an iOS app out of it. I'm not sure of any method to convert Python => Swift like there is with Flutter.
Your information is a bit outdated. Since version 4.4, Electrum uses QML/Qt for Android, which is also compatible with iOS. Instead of converting Python to Swift, one can use Python with QML and build the project via Xcode. There's no need to rewrite the app in Swift, as QML/Qt supports cross-platform development, simplifying the porting process to iOS
Without reproducible builds you don't know if the executible has been created by exactly the published open-source code. And that means that you have to trust the developer that his public source code is exactly and only the source for the executable.
It's not much better to my knowledge (I'm no developer, so I could be terribly wrong) at Google's Play Store. To my knowledge there's no user verifiable metric to check if an app's executable code has been derived from a certain public source-code.
Fdroid's app store for Android is a bit different: to my knowledge it accepts only open-source apps and Fdroid builds the published apps by its own build infrastructure. So you can only download an executable from the source code that Fdroids infrastructure sees or has. Well, you have to trust Fdroid then that their builds don't sneak something in.
I understand the concerns regarding reproducible builds, especially on iOS, and I currently don't see a viable solution to this issue. But if anyone has ideas regarding reproducibility, I would be happy to hear them. However, the absence of the Electrum wallet is also a significant problem for iOS users. I find myself using BlueWallet instead of Electrum, even though I would prefer to use Electrum on my iPhone.
Additionally, the lack of an official wallet in the App Store opens the door for phishing applications, which could be avoided if Electrum were available in the store. Therefore, I plan to create my own fork in the near future. The account costs only 99$, and it allows for the publication of Electrum and other applications, which makes it a small expense.
For now, I am focusing on the technical details to make this happen.
It was posted a year ago; you can maybe check his old post on the github page to get some idea and if you want to participate for IOS version.
Unfortunately, I don't know how to achieve that at the moment, and I've decided to focus on creating my own fork for now, as it is significantly easier and faster. If I manage to achieve reproducibility in the future, I would be happy to reach out to them.
If anyone has advice regarding the fork or suggestions for features to add to the iOS version of the wallet, I am open to hearing them and will try to implement them now