For example, when testing every single X870/X870E motherboard, we found that about half of the 21 boards tested worked with DDR5-8000, while the rest were unstable or simply failed to boot.
This is brutal. I am happy that I have no plans to upgrade till at least Zen 6 (and probably the next AMD GPU generation; this may be my first non-Nvidia GPU since my family switched from S3 ViRGE to Riva TNT a quarter of a century ago).