Not to go way off topic, but One UI or whatever Samsung calls their UI now, still does indeed have slight microstutters, and very slight minimal hiccups. Which I never see on a OnePlus phone, and very very rarely on my Pixel. My most recent Samsung phone was the Galaxy S8+, and it absolutely lagged, fact. My office crew here has Note 9's, and I had to set them up for everybody, and yep, those for sure had slight microstutters that I rarely see on brand new phones. And I know when the phones is new out of the box there's a lot going on and downloading and installing. But I'm talking about after it's settled in, and totally up to date, and complete, these Note 9's still surprised me with some hiccups and very minor lag I wouldn't expect. I remember when the office here all got Galaxy S7 Edge's LOL holy cow those lagged like an old Windows 95 PC, that phone sucked so bad, all 8 of them here I was in charge of maintaining were horrific with lag and stutters and slowdowns
Now, I have not played with the S10, or Note 10, maybe Samsung finally is as smooth as Oxygen OS from OnePlus?
In my opinion, the smootheset lag free phones are;
-OnePlus
-iPhone Max
-Pixel
-Samsung and LG at bottom