Sure, back in the iPhone 4/4S days iOS 7 trashed older phones. Unusably bad. Should never have rolled out those UI updates if they couldn't perform well on older hardware.
These days? I'm using a 2016 SE with iOS 15. Works great. I do not hate my phone. In fact, the small size, fingerprint sensor, and headphone jack make it a better buy than any modern smartphone. I can live without AI text recognition on my photos, which seems to be limited to newer phones. The app switcher, settings, browser, and everything else are still as snappy as the day I bought this thing. Only thing that doesn't run well? Spotify, which apparently doesn't bother to test their UI on small hardware (constantly clips links and text off the bottom of my screen), nor older CPUs (the app takes forever to start up, regularly freezes up when searching for songs, and can take anywhere from 1 second to 30 seconds to load even already downloaded albums).
