Actually, there's no Electrum installer for iPhone they only support macOS, Android, Linux, and Windows.
And it seems Electrum developers do not have a plan to develop Electrum app on IOS because even if they do release Electrum for iPhone you can't able to install the app if it came from directly on electrum.org.
There's news making the rounds that Apple has plans to enable support for 3rd party app stores (but only for users in Europe). Although I don't know how that would work, I suppose this means that something like the equivalent of F-Droid can be made by some people, and Electrum can publish their app on platform, or even provide a binary that you can download, but opens with that app store by default for the purpose of installation.
It seems that I found the news you talking about here
Apple may plan to appeal against the EU App Store law it was published 3 days ago.
According to it "Apple’s engineers have already developed tools to permit third-party stores and app sideloading on its systems, at least in Europe"
That's good news for those who live in Europe but how about other countries? Actually, you can install apps from 3rd party the only problem is you will need to jailbreak the unit to be able to install apps outside the appstore but it's not permanent once you turn off and on the device, the jailbreak is gone and all 3rd party apps won't work.
And another problem is we do not know how safe is jailbreaking just like on Android phones if you root your phone you are vulnerable to any attacks online just like what happened to my old phone which has lots of malware and ads when you connect online.
I hope that Apple decides to support other countries too so that we don't need to use any tools just to jailbreak the unit.