Got mine today. I do notice some jelly scrolling but I am not sure if I would have noticed it really had I not been aware of it beforehand. I also have a mini 5. I am in love with this device so far and will be keeping it. Maybe I just got lucky?
The "lucky" part is that it does not bother you personally.
Every single iPad Mini 6 is exactly the same in this respect. Even Apple confirmed that it is just the way it works.
AFAIK, there have been zero reports of anyone trying multiple iPad Mini 6's and finding any difference between them (for jelly scrolling, that is). To the contrary, there have been reports of people going to the Apple store and finding that every Mini 6 is the same.
I suppose it is possible that someone might convince themselves there is a difference from one Mini 6 to the next, but this is likely just wishful thinking.
I am only pointing this out so that people don't bother trying exchanging for another iPad Mini 6.
I suggest just bask in your luckiness, and don't try to look for the jelly scrolling!