While this is anecdotal, they don't always run smoothly at least statistically, and no software is always flawless...
Arguably one could say that the major iOS versions don't have major differences while Android does. E.g 9 to 10 has major graphic stack overhaul and 12+ has major app API changes. iOS 12-13 is significant while 13-16 has less core changes and more UI/UX relatively etc. Android upgrades are technical and under the hood, usually hardware specific changes and API. Most people can't tell between Android 6 and 14 with vendor skin/theme.
The point is you can keep an Android phone updated without changing the major version. You don't have to update the entire OS for the notes app like in iOS which I had to do because the Mac app refused to sync. You could also get major UI changes and new OS integrated features like quick share with app updates on the same Android version.
Changing battery on any modern smartphone isn't easy and very risky for the average person.
For the younger crowd, checkout smartphones before 2016, many had the ability to replace the battery under 10 seconds, though the point is that it's user serviceable.