Yeah, they’ve kind of inverted the issues:
32-bit devices: unusable performance, good battery life, and the opposite for 64-bit devices. The iPhone 6s, the iPhone 7, 1st and 2nd-gen iPad Pros, etc.
iPhones with larger batteries haven’t been rendered unusable (the iPhone Xʀ is usable), but it’s been degraded to a mediocre battery life device, with the same battery life as an iPhone 6s on iOS 9 or 10, whereas I’m probably getting a little over twice as much battery life. As battery sizes increase, usability improves even when updated, but nobody can tell me that the iPhone Xʀ has good battery life today. It’s moderately usable and shrouded in mediocrity, and that’s as far as I’d go.
As a user of the Xʀ on iOS 12 today, it’s sad to see what they’ve done to it.
Hopefully the 3rd-gen iPad Pro fares a little better on iPadOS 17, obtaining iPad battery life reports is a little tougher. OP no longer has theirs, it’d be interesting to know how much has the degradation been.
Battery didn't have much degradation. I had over 1100 charging cycles and the battery health was at 60-90% (I'm not sure which value to look for). I was charging it pretty much every day.
But I disagree on your don't-update-philosophy. Your device is going to be full of viruses. Every website you visit makes a ton of connections with your device, you device downloads all kinds of stuff without you even knowing it, etc. Your device literally must have Aids, lol (nothing against people with Aids, stay safe people).
In my opinion the problem is that 1) Apple wants to release a new OS every year, even though there's no use for it. It could be just a "normal" update. I would prefer if the focus was on quality. But Apple is all about cheap plastic. And 2) I think Apple is consciously slowing down old devices to make you buy a new one.
There's no technical reasons for a new OS to become slower when browsing menus or typing on a keyboard. I could relate if the old device failed to run new software that needs a lot of CPU which the old device doesn't have. However, the new OS hasn't changed anything to either typing on the keyboard or browsing the home screen, yet exactly these things are becoming slower.
On top of that, as a Mathematician, I must say the cycles in which this happens correlates so well with new devices Apple is releasing, that it is statistically extremely improbable that these events happen at the same time. In mathematics, with different tools, you can tell if a correlation is coincidence or if it has other underlying variables that control it, and in this case, my opinion is that it is a process controlled by Apple and not a coincidental correlation (which would be
extremely improbable according to probability theory anyway), but rather is a controlled correlation to make it look "as if" devices were getting older, while they're actually being "damaged" consciously.
In my eyes, it makes Apple look like a gangster firm. And perhaps it is moving in that direction, who knows. Times have always been changing.