iPhone 13 mini: Performance & battery issues after iOS 26

I updated my iPhone 13 mini to iOS 26 a few weeks back. I am now running iOS 26.2 and I am not at all happy with the performance. It does not seem optimized for older devices at all. I am noticing a significant performance decrease (e.g. lag in app animations, especially Duolingo, slower app response) when compared to iOS 18. Also, my maximum battery capacity was standing at 97% just roughly 2 weeks ago (already about 2 weeks after the 26.2 update) and it has now deteriorated to 95%. I also notice decreased battery life compared to iOS 18. Is anyone experiencing similar issues? Can I analyze what is causing this?