I really don't care at all about phone models, I just want software to launch quickly.
Waiting 15 seconds for a simple app is just infuriating in this day and age. This is mostly on crappy app developers, but a lot of that falls on Apple for not having a rating system that encourages basic good app behavior.
Every bad app that I encounter, which sends advertising notifications, takes a long time to launch, etc. is dominated by 5 star reviews, somehow. The whole ecosystem feels broken.
(And I'm also really offended by how ugly, unpolished, and broken the Tahoe visual style is on iPhone. The whole thing feels like a buggy beta, something completely unworthy of Apple of the past. That it's still not fixed is an indication of the Apple of the future, unfortunately...)
Maybe you need a new phone. Or a faster internet connection?
I just tested a number of apps on my 15pm connected to WiFi and could not find anything that took longer than 5 seconds. That includes some small developers and bad developers.
Not quite sure where you are seeing this. Maybe games?
I try and pick apps based on package size the rare time I look for some app. There are still apps out there made like they were 10 years ago (that probably haven't been updated in 10 years) where the package size is sub 10mb, sometimes sub 1mb. You get an app like that it is performant and will fly on any iphone really, and barely impact battery life in all likelihood.