While I don't think that is your problem, yes there is a difference between top tier brands for upscaling Samsung and Sony and next tier including Vizio and then lower tier hisense etc.
Before I increased the anti-noise setting on my Hisense, it looked a little grainy when viewed at very close range. I figured the upscaling was awful on the Hisense, so I bought a cheap 4K Bluray player, and it exhibited the same issue when upscaling regular DVDs or regular HD Bluray disks.