Even on my home server (a desktop with 64 gigs of ram) the ram check takes longer than the OS.
I was pretty sure I messed something up when I upgraded the RAM in my desktop from 16 to 64 gigs and it wouldn't output any signal for solid 10 seconds, lol. And the regular 5 second black screen on normal boots was still something I had to get used to coming from maybe a second with 16 GB
box86/box64, and there's also FEX-emu which is used by the Asahi Linux project (Linux on Apple Silicon macbooks).