Are high sample rates making your music sound worse?

I did my best to evaluate precisely that. The WAV file being the reference, (which included click/noise reduction) I experimented with many iterations of LAME/MP3 settings until I could not tell the difference in the conversion. I don't consider my ears the best, as they've been abused/damaged in the workplace. So these 'other' ears are a valuable resource for this result. And I edit in 32-bit on purpose, not 16.

Vinyl is reported to have a noise floor of roughly -65dBFS, so I don’t see how any ADC or conversion technique can make it better than CD at -96dBFS, unless you are adding noise-shaped dither, in which case the same can be done for 16/44.1.

I submit you may not have experienced the range of features and options available in Adobe Audition. Adobe purchased Cool Edit 2000, and has made a lot of improvements. (I started with Cool Edit 2000)

Audition's 'Analysis' of LPs before click and pop and other noise reduction says LP dynamic range starts in the 40s for bad ones, and I'll agree with your number of 65 for only the very best. (very rare) I can't recall the last time I saw one that good. They are typically in the 50s. (per Audition)

Just to mention that the figures touted for CD SNR and Dynamic Range of 90 dB or more are strictly theoretical. In practice the ordinary drawbacks of the playback system and room not to mention the *intentional overly aggressive dynamic range compression* that’s fairly rampant in the industry over the past twenty years or so obviously limits those numbers. How much? Answer at 11.

The objectively BEST sample rate for playback ... drum roll please ...

Is the one used in the mastering room

On the approved recording.
There is no gain to moving from there, and with something like MQA that adds distortion, there is a loss in quality.
Having said that as #1 the next factor in listening is your room. Most rooms are not good, and sure we can put $20,000 or $200,000 in gear in a bad room ... but it’s rather silly if you understand the room to be over 50% of the sound from a pair of speakers. And if you doubt that figure, set up the hifi in the garage or basement.

but it’s rather silly if you understand the room to be over 50% of the sound from a pair of speakers. And if you doubt that figure, set up the hifi in the garage or basement.

I would honestly say this is conservative. I've measured rooms, and with +- 20 dB nulls and peaks, a room can have tremendous effects on the output power in the bass, the timber, and the ability to resolve spacial cues.

It is also true that we can train our ears to reduce some of these effects. Try recording a person's voice, or just your stereo in a room, then listen to it with headphones. You'll be amazed. With training, you can teach yourself to stop blocking this, and you suddenly can hear the room itself.

Best,
E