Real time upscaling on different TV´s ?

[BrightShadowDK]

Hey, Im still rocking an 8+ years old SONY 40" 1080p TV (KDL-40EX500) and i has been more than satisfied with it..

but last week i giftet a 49" 4K LG (LG 49UK6300) to family, and must say that i is impressed to see what you get for such a small amount of money today.. (295 USD)

i thought i'd go from a 40" 1080p direct to 65" 4K but seeing the 49" in a living room i must say that 49" is fairly large (they jumped from 32" to 49")

ther wiving distance between 3,5 meters down to just over 1 meter..

My problem as a geek comes when i see the tv scales 1080p impressively when as long as it is not action scenes, even gaming on PS4 (NON PRO) looks sharp AF..

but watching a older movie as Triple-X (No not the XXX kind, get your mind ot og the gutter) no the one with Vin Diesel..
it was constantly switching between upscaling slow uniform senes almost perfectly (to 4K)
and then the next moment in action scenes it looked like 480p... WTF ! (Netflix Premium)

My thought was that processing upscaling on fairly uniforme pictures is a lot easier for the chip than constantly changing action shots !?

so my question is: do more expensive TV´s upscale action better ?
if not i will properly go with a lot smaller 4K tv than 65" only got 2,5 meters viewing distance i my own living room..

Btw. i'm watching a lot of Youtube (also older low res.), Netflix and browsing from my HTPC (with adblock)
so i´m NOT gonna go with OLED because i'm gonna be a prime kandidat for burn-in..

(i guess there are no chance of using the PC´s horsepower to pre-upscale?) 

My budget i around 1000-2000 USD (bought i Denmark)

Kind regards from Denmark

[circeseye]

some do have better but it is what it is....older movies depending on the media dont look very good. older movie even remastered ones sometimes dont look very good
1080 movies look fine
720 look ok depending on encoding
480 you really start seeing quality issues