I've tested the JPN versions of sfz3 and cvs2 but I couldn't get it to work at all. The games wouldn't load in Retroarch. But the US versions work just fine. I never owned a Dreamcast so I'm not sure if something needs to be changed within the core options for JPN games to work properly.
Also, my setup is very different. I'm using Linux (Manjaro) as my operating system and these specific arguments because I had to unzip the files. I couldn't run any games in their .zip folder. So as long as the .gdi matches up exactly with their folder name, I can run all of the games in sub folders.
# Generated by Attract-Mode v2.6.1
#
executable retroarch
args -L $HOME/snap/retroarch/393/.config/retroarch/cores/flycast_libretro.so "[romfilename]/[name].gdi"
rompath $HOME/Desktop/GAMES/dc/
romext <DIR>
system Sega Dreamcast
info_source thegamesdb.net
artwork flyer
artwork marquee
artwork snap $HOME/Desktop/GAMES/dcvid
artwork wheel