As much as I love OLED it really comes down to what fits your room better and when you watch tv the most. Say if mostly in the evening, this issue with natural light would not be an issue. My friend is debating these same models, and I told him even if all prices were equal I'd still say QN90a over the others - because of his room. The only OLED I maybe would recommend for him is if he got a 77 inch OLED, because the larger the screen, the brighter the panel. He has a sliding glass door not too far from his wall with the tv, and some overhead skylights - I just think it would be too much natural light and would have reflections galore. All tvs will have glare, but a brighter panel combats this better. I believe Best buy has a 15 day return window. If you have a costco membership I think they have 90 day return policy + some complementary extended warranty. Either way it is going to be a birch repackaging a large tv to return. Display models in the stores are cranked up to max brightness usually. This is nowhere close to what it might look like in your room, plus the lighting is completely different in a store vs house.
Qn90a, A80j, A90j, C1, G1 all have atsc 3.0