I built an app that is running mainly in a Samsung tab A7 lite.
The app itself is pretty simple, no internet connection, only uses a local SQLite, no complex operations, no custom animations, but the performance is shit, its usable, but there is clearly a lag.
Though testing it in my phone (Redmi Note 10, not high-end at all) I have no problems with performances.
I test the apps in my company using a Tecno Pova 2, and the performance is far better thab my Samsung device.
Our apps contains lots of features, for example we use lots of media streaming (video player, google cast, pip, airplay), we use webviews to display our content for better compability with our websites, and AdMob. The main problem is the number of Ads used, however these are requirements from the client.
I've used very low-end devices with no lag, so this is surprising. I've always had more consistent performance in flutter, and the smoothness is usally what tips me off. React Native tends to be very fast though, since it uses native views.