I went thru a search, my conclusion is it’s like a salad, a mix of processor(s), anti-jitter; over-clocking; proprietary filtering ..... You have to hear the result yourself, best of luck with selecting which one to try, perhaps buy where they allow returns.
I am so happy with my Sony xa5400es SACD/CD Player.
I had been solidly vinyl since overhauling my setup starting in 2019, then I asked for SACD advice here, and found a lightly used one. Lasers get weak with hours of use, not age, and finding the SACD layer is typically the first thing to go.
I re-discovered my many CDs and SACDs, and actually have been buying used CDs, it sounds terrific.
New laser assemblies are still available
Also, whatever you do, pay attention to DSD/PCM Conversion, if you care

