The long POST times are a consequence of DDR5 link training. It's not entirely an AMD-specific problem. Most motherboards for either Intel or AMD now have a feature to skip most of the link training if it doesn't look like there's been a hardware change or since the last boot, but it's unavoidable on the first boot.
30 seconds would be a blessed relief. Link training takes upwards of 3 minutes for my 4x 32GiB DDR5 machine whenever I update its firmware, and then 3 minutes all over again when I load the XMP profile instead of running at the new firmware's safe stock 4000 MT/s.
