It is a little superior than A6K as the U6K offers Local Array Dinning giving more deeper Blacks. And it is a 2023 model.
What according to you should have been the good price to pick up the U6K ?
And how does keeping motion smoothening to minimum and off help ? What does it do ?
I did mention sometime earlier that U6K found on EU/US that is reviewed by rtings.com is not the one sold in India, Indian 55" U6K claims 32 zones vs 120 zones claimed in rtings.com. Hence I recommended A6K instead or cheap Samsung/LG models or Sony X74K.
Do a FALD test, to see those zones:
www.youtube.com/watch?v=3So8OFdqcdA
Like for my monitor I can't see any light zones turning on/off. On OLEDs as well you won't see any zones turning on/off because each pixel is a light source there (perfect panel). But in cheap TVs with say 32 zones, etc, you can see the zone transition with visible light trails.
Anyways, enjoy your purchase. As I mentioned, even a 55" A6K will feel like a big improvement to you, so U6K will definitely be a huge improvement.
I don't like the soap opera effect that motion smoothening results in, hence I keep it off usually or low (put it at low for Panasonic 4K TV with my parents, off for flatmate's A6K). Experiment yourself & see. Bigger brands handle motion smoothening much better. I checked a friend's LG G3 last weekend, he had motion smoothening on & the cricket match on Sunday did look great on it even though I hate it on other TVs which are usually cheaper (it is LG's flagship TV, so obviously its great).