98 v 85 QM6K (Pro) vs QM7K

Feel like I'm beating a dead horse of a daily question around here but I've read enough and not really seeing this direct discussion.

Here's my issue- Just got the Costco 98" 6K Pro and while the HDR viewing seems great, watching football Sunday in seemingly SDR format was at least 50% of the time terrible image. I find that when they are zoomed in more on the image it turns pretty good looking but as soon as it zooms out like a play is starting the image went to blurry/halo'd crap. And the motion seemed pretty nasty like the players running or ball flying.

For reference: Viewing distance about 13.5-14ft Fairly bright daylit room but dark out when viewing to make my above observations. Streaming YT TV (tried though firestick 4k max and directly through the Google TV) Tried all variations of settings from Rtings and suggestions on here. None really seemed to change much.

So I guess my main questions are: 1. Does a 98" screen inherently make it worse than an 85" will look under same conditions? And same tv model?

2. Is this to be expected viewing content that is not a 4k stream?

3. Would moving up to the 7K or even 8K all other things the same have any actual effect on improving picture quality?

I think I get the 7K is much brighter and that's what seems to be the main step up from 6K. But I don't think brightness is really my issue? I already have to turn down the 6K because I find it too bright at 100.