OLED is a type of TV display technology. You cannot have OLED players. In terms of technology itself, this is it for 4K blu ray players. There may be variations in software to include Dolby Vision etc.
Your TV is doing all the upscaling (so no need for an upscaler to be present in your blu ray player), and from what I have seen, the upscalers in the TV are brilliant on their own.