"How big of an issue is it to target iOS as a platform on a PC these days with the rise of Flutter, etc?"
Flutter is nice. Yes, a single codebase typically works both on Android & iOS (sometimes, a little tweaking on each platform is needed).
The problem is: you can't avoid iOS SDK for iOS development. This is not Flutter-specific, BTW, but everything: React Native, Ionic, Xamarin, Pascal etc etc. So you need to have either a Mac machine, or access to Mac cloud server.
I vote the former, because it makes debugging easier.
Flutter is nice. Yes, a single codebase typically works both on Android & iOS (sometimes, a little tweaking on each platform is needed).
The problem is: you can't avoid iOS SDK for iOS development. This is not Flutter-specific, BTW, but everything: React Native, Ionic, Xamarin, Pascal etc etc. So you need to have either a Mac machine, or access to Mac cloud server.
I vote the former, because it makes debugging easier.