In showroom lighting, OLED won't look the greatest because it can't get as bright. That's why Samsung outsells every other TV maker by a landslide despite having mediocre TVs.
In your home with appropriate brightness with curtains and decent lighting, it will come to life. I had a B7 OLED back in Bengaluru and just basic light-blocking curtains from Amazon basics make a massive difference.
I absolutely agree. If your viewing distance is over 6 feet, 65" over 55" will make a much bigger difference than the PQ differences.