If you want an "easy" way to dump the CD bios from real hardware, here is a link that is about as easy as it gets (aside from the supposed flash cart way that I don't personally believe is real)
https://www.retrodev.com/transfer.html
The problem is, it requires a PC with a 25pin parallel port, which probably means you're talking a 10+ year old desktop PC or older laptop and likely was designed for WinXP at best. I used this software myself back in the day and it was easy for the n00b I was at the time. The hardest part was burning the iso to put in your SegaCD (at least it sucked on XP back then, LOL) and building the cable is easy unless you have ZERO soldering experience. If you can solder one wire to another you're fine tho.