The parts on 35 you talk about were simply scenes pulled from Fire Walk With Me or the original Twin Peaks. Other than that, it does look very flat like you say, I'm not sure many people will comment here, there's not much to say imo.
Twin Peaks to me, watching it for the first time on Netflix, has a lovely look and it is jarring to switch to digital, but Twin Peaks The Return looks fairly pedestrian, seeing a lot of the stuff on Netflix right now like Dear White People, or Glow (especially with the 2:00 AR), or other shows like The Leftovers or Fargo, I'd say it's one of the least cinematic shows around, I'd argue that actually it very much looks like some of the middle of the road stuff we otherwise see on TV.
It's probably sounding like I'm ripping into it, but imo The Return is the best Twin Peaks has ever been, and I don't think the visuals matter much here. I'm bummed Lynch didn't go for film, he said he would for this, had a change of heart.