There was the dell S3225QC for $350, 32" 3840x2160 oled 120hz that Tp4 urged everyone to buy from Costco recently, But it's probably out of stock now in most places.
If you want something like that, you'll have to go to the $500 sale range, 165hz 4K OLED from MSI or Asus, usually Newegg.
Tp4 however recommends the new iterated dark film covered QD oled models. They're all using the same samsung dark film panels, but call it dark armor, etc, etc.
4K 240hz is great, will be in the $600-800 range, 4K 360hz is incoming, probably $1000+.