To fix that, a new panel. I am guessing this was not there when new and it's just aging.

Pixelly is something folk complained a lot as the move from ratty NTSC to digital happened. There's a limited color palette so it would take a long write to cover why. But pretty normal and upsetting to folk that want pixel perfect screens.

Not that all is lost here, move between various shades of that color." That reminds me of Samsung Plasma sets that the tech needed to adjust drive levels. Not user serviceable so get an estimate.