Buying a high dollar item I typically run a lot of tests looking for a flaw, but you are right about panel lottery theres no guarantee you'd get a replacement which would have been "cleaner". I think SOME stores will let you unbox it and test it in stores, but it that might not be an official policy. DSE can be pretty annoying from what I've read. I've seen people comment as: "once you see it you can't un-see it". I don't think I personally could buy and LED tv online that had no option to return it to a store. I don't think it is limited to just a samsung thing though, because global consolidation results in only a few companies making LED panels nowadays. For OLED tvs LG basically supplies everyone else.
so for the rest in regards to viewing:
A lot comes down to mindset and intent. Say if you were a cinephile, you'd want the best conditions and accuracy. What is fine for one won't be for others, nbd. Each person is different there is no one-size-fits-all type of answer. There are some Tvs that perform better (or worse) in certain situations, but those situations and results will vary from person to person, as will what they find acceptable or objectionable as you put it. Like for you DSE far outweighed the rest. I'm actually with you on this, I don't think I could tolerate it myself hah
I just put out info and let people weigh the pros and cons. There are actually some models on a higher tier than the ones I listed, but I doubt many here would be looking to spend $3700 on a 65 inch A90j (even if it is technically superior to all other sony/lg OLED tvs).