I recently purchased a pi 4 with 4gigs of memory to co-exist with our new LG smart tv. Found out that the LG app store doesn't have a lot of apps, we normally used PBS Kids and NHL for example.
We have been using PBS kids just fine watching cartoons works great no choppy video at all. Since the hockey season just started I signed up for a subscription and got it all setup. The video while action is going is just quick little chops mostly then will smooth out if they switch cameras to the announcers.
My video settings in Kodi are
Adjust display refresh rate: on start/stop
Sync playback to display: off
minmise black bars off
display 4:3 videos as: Normal
Render method: Auto Detect
ENable HQ scalers for scaling above 20%
Allow hardware acceleration - MMAL: On
I even enabled a Sports Picture mode on the TV's display settings, which enables TruMotion.
Update: I brought it down to my computer monitor with the resolution of 1920x1080p and it has no issues playing video from the NHL addon. There must be something about it not liking the 4k resolution I am guessing. Tried to even lock the big screen at 1920x1080p resolution but even at that it was still choppy.