First, I want to be clear that I am not trying to provoke heated argument, but appreciate that this is a controversial topic. Second, I am only interested in the results of properly-executed, methodologically-sound, statistically-valid double-blind experiments. Third, I am aware that some purported differences are worthwhile, but they are due to different mastering or artifacts of other differences, as opposed the actual Hi-Res vs. Redbook CD bit-depth and sample frequency. Fourth, I am also aware that just because some people can differentiate the two, it doesn't mean my over-50 ears can.
With that preamble, I saw a large meta-analysis from 2016 that showed that some people can beat random chance differentiating Hi-Res audio, but was it done well? Meta-analyses can be flawed, just like any other research. Also, I know that a novice is not in a good position to judge whether specialized research valid. (Though a novice can sometimes see when a study is clearly not valid.)
As a bonus follow-up, not necessarily related to Hi-Res audio, though I've seen it discussed relative to enhanced up-sampling, is there currently any Artificial Intelligence or other advanced software that can improve audio files. Just as with computational photography, you can't guarantee that you're putting back something that was present in the file, but you can add something in based on knowledge of the world previously acquired.
I look forward to hearing what people have to say.
As full disclosure, I do own a small amount of hi-res audio, including DSD. I sometimes believe I can hear the difference, but I know that doesn't say anything about whether there is--either because of my expectations or because of artifacts in the process. Regarding AI to improve files, I doubt there is anything too magical, or I probably would have heard of it already.