If I might give you a heads up here, they are not the best. For a reference player look at Magnetar.
My dream setup is a Magnetar UDP 900 MK II and a Leica Cine 1...
Didn't even know there was such a thing... Knowing Leica cameras, I'm afraid to ask about the price. Well, like they say: if you have to ask... :)
It gives me hope the future is not completely lost.
it typically offers better video processing and upscaling, more accurate color reproduction, cleaner gradients, and superior HDR handling (including dynamic tone mapping on some models). Many also support Dolby Vision from UHD Blu rays, which the PS5 does not.
It won't show on a bad screen that much, but a dedicated player will squeeze out more of the disc.
First, the player performs MPEG-4 HEVC decoding, reconstructing full video frames from heavily compressed data.
Once decoded, the signal is still not in a display-ready format.
UHD Blu-rays are almost always encoded in 4:2:0 chroma subsampling, meaning luma (brightness) has full resolution, but chroma (color) is spatially reduced. so one of the first steps in the pipeline is chroma upsampling (chroma reconstruction). After that, the player applies color space conversion and output formatting, usually converting to a HDMI-friendly format like YCbCr 4:2:2 or 4:4:4.
HDR handling is sometimes done on the player. The tv is doing a last stage processing that is fine tuned for it's display like contrast enhancement.
I hope that helps
HOWEVER, there is an exception: Feature support. For example, not all blu-ray players support 4K blu rays. Not all players support Dolby Vision.
If you try to play a 4K blu ray disc in a non-4K blu ray player, it won't function at all (won't read). If you try to play a disc using Dolby Vision in a player that doesn't support it, it will fall back to HDR10.
But assuming 2 players both support the features a disc uses, the end output will be identical.
There's also upscaling, which some players can do differently.
the final output is not guaranteed to be visually identical because parts of the processing pipeline (chroma reconstruction, tone mapping, scaling, and output formatting) are implementation-dependent. There is a spec, but multiple processing stages are not strictly defined to be identical. Higher end players also use a HDR Optimizer and the ps5 does not, which is visually noticeable.