You might consider M-Discs, which are optical discs as large as 100 GB (BDXL) that you can burn yourself, and which should have the same longevity as a CD-ROM.
Of course, if CDs are working for you, this may not be a problem that needs to be solved. ;)
It's not clear to me that there's anything special about the BDR M-Discs vs. other BDR discs.
It looked like original DVD M-Discs have been discontinued, last time I checked. IIRC, those where the things that all the articles about M-Disc longevity were written about.
(In particular, I think there was an article on HN a few weeks ago that did tests with both M-Disc BluRays and another brand. The M-Disc wasn't magic but it was a decisive winner.)
That's interesting. However I still have a couple questions:
1. My understanding there are significant brand-to-brand quality differences with optical disks. A better comparison might be Verbatim regular BDR vs. Verbatim M-DISC BDR than TDK regular BDR vs. M-DISC.
2. That article is from 2016, and I wonder if it holds up. From what I've read about optical disks, even were the disc was manufactured can be significant within the same brand. IIRC, back then they might have been making them in Japan, and I don't think they do that anymore.
Not necessarily true: they do degrade over time. DVDs are even worse, so I imagine (without evidence) that Blu-Ray discs are even more sensitive.
Really, you want to move your physical media to lossless digital as soon as you get it, and store it in a format that is both backed up and resilient to bit flips.
CD-ROMs have physical pits etched into the plastic, as do mass-produced DVDs and BDs. These advantages don’t apply to discs you produce yourself, however.
It can happen, but it’s rare—not so rare that I forgo backups, but rare enough that I continue to maintain an archive of actual CD-ROMs.
CD-ROMs last a long time, unlike magnetic media, SSDs, and CD-Rs. If I buy a CD-ROM, I know it’s going to outlive me. I often listen to artists who disappear—along with their libraries. Some produce actual CD-ROMs before disappearing, though that seems like a poor investment for an indie band.
I carefully back up my music, but nothing I can make is as durable as a CD-ROM. Cloud backups are great, and I have plenty of local copies, but that CD-ROM beats them all as long as my house doesn’t burn down. It’s not going anywhere.