[mchinen]

Most of the work on objective quality metrics (e.g. PESQ, POLQA, ViSQOL, DNS-MOS, NISQA) focus on speech because of telecommunications demands, but some of these have an audio mode. But there are some new promising audio ones that are ML based.

I haven't tried it but you may want to look into PAM, which is relatively new and doesn't require a reference (you don't need the original uncompressed audio), and is open source.

However, all approaches are quite far from perfect. Human evaluation is still the gold standard.