Instagram stuttering vs

I bought an iPhone xr 4 months ago. from the first time, I experiencing animation stuttering in opening or closing apps. even I saw this stuttering in animation of all apps.

for example, in Instagram app the animation of next story or scrolling stutter. in Whatsapp the animation of receiving a new text stutter.

This lag is not constant issue and it's intermittent. I use iOS 13.4. restoring iOS and erase all the content and settings did not work.

anyone have the same issue? I hope this is a software issue.