iPhone 13 Pro jitter and stutter iOS 18.2

I came from this post as it’s closed for me and I can’t reply there https://discussions.apple.com/thread/255447241?login=true&sortBy=rank

i bought a refurbished officially iPhone 13 Pro and first what I noted was unbelievable jitter and stutter of gui animations, everything lagged, scrolling, changing apps etc, then I noted that keyboard swipe doesn’t lag, I initially assumed that replaced screen is bad quality and itis causing jitter, later I installed 3d games and they didn’t lag, so screen was capable of smooth animations. I started to google and found the thread. Proposal to turn off the auto brightness didn’t help much, I also assumed that touch data might spam from replaced screen and caused system to stutter, so I experimented with touch input filtering settings to not pass duplicates every 0,5s, it doesn’t help. And I almost gave up and wanted to trash the phone as I couldn’t believe how bad it was, my old iPhone XS and my wife iPhone 12 Pro doesn’t lag at all on latest iOS and on 17.4. So I accidentally saw the setting to limit fps to 60hz instead of 120, it’s in settings > universal access > motion > limit fps checkbox. And wow the phone became super smooth. I don’t care if it’s not 120 as it feels very consistent and smooth as my previous iPhones now. My assumption is that it doesn’t capable of 120 hz due to older gpu and new more greedy iOS, so limiting to 60 frees some resources and there are no more fps drops and stutters, hope this helps somebody as I couldn’t find the answer and spent several hours troubleshooting the bug.