Bloat like that is usually due to unnecessarily convoluted tech stacks pulling in a list of dependencies that goes out to Mars and back, or for globally targeted apps sometimes it’s translations for everything in the app for hundreds of different languages.
Cross platform frameworks really aren’t the magic wand they’re sold as.
Disagree about UIKit, mainly cause of Autolayout, unless it's gotten reworked in the past 8 years. When I started using RN, I had zero web experience, and still it was way quicker to set up a basic UI than in the UIKit stuff I'd been doing for years. And for all that setup, Autolayout doesn't even seem to future-proof your stuff that well. An abandoned ObjC iPhone app I wrote in high school using C-style macros for layout worked perfectly fine on the newer screen sizes that broke most other apps.
I thought maybe I was stupid, but the other iPhone devs I worked with constantly had problems with Autolayout. Maybe a real expert iPhone dev won't, but it shouldn't take that.
Pure code UIKit using autolayout’s anchors API is quite serviceable, and if you follow recommendations (use safe area and keyboard constraints! They exist for a reason) reasonably futureproof. The iOS apps I’ve worked on have needed very little change year to year for quite some time at this point.
But this is still incredibly ridiculously comically gross. The fact that we can afford it these days is an irrelevant seperate thing. These numbers are just unjustifiable for what most apps actually do.
For a couple examples pulled from my TestFlight list, there’s a social media site reader app that’s 7.6MB and a text editor that’s 697KB. Those sizes aren’t the least bit unreasonable.
Heck, if you are a world business and the app isn't your core value prop, whats your case for investing anything more than the bare minimum in creating your app?