Actually I don't know why people say that oled are best for dark rooms. Its brightness is is too much for my eyes in dark room even for normal contents (HDR is way more brighter).
How else will you sell the most costly and inferior samsung qleds? A bit of rumour like this goes a long way.
I have not seen a single owner replacing the oled with qled for lack of brightness.
Oled is endgame for most people. I got mine for double the amount you paid 3-4 years ago.. Hopefully they become more affordable so that most people can enjoy the splendor.