There's a bit of misinformation here. At the end of the day, a blu-ray player is reading information from the disc and passing it onto the TV digitally - one player or another are going to do that identically. One can't have 'better color' or anything like that.
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.
Hu?
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.