Anyone know where I can find vgm or s98 files for Rhyme star? It seems a lot of Abo's works are missing....

might be what youre after
https://github.com/czarek7711/hoot/blob/master/pc98/rhymes98.zip

Rhyme Star uses the PC98 86 soundboard to play the PCM so it cannot be logged as VGM or S98, only way to play the soundtrack files is through PC98 emulation or Hoot (sound driver emulation). If you want only the YM2608 part you can log it yourself with nekoproject.

The sound driver doesn't have support for ADPCM. Other PC98 soundtracks have this limitations to keep it from being logged(i.e. the non-YM2203 version of Eve Burst Error) but usually there's an ADPCM version of the soundtrack if the driver allows it.

Ok I was able to use Neko Project to make a .s98 file, but now I'm looking for a s98 to vgm converter (minus the ADPCM of course). I'm code-illiterate so an step by step would be helpful

Edit: There's a modded version of Neko Project that allows for .s98 AND VGM logging works pretty well so far (No ADPCM channel but you can just record drums from Hoot as a wav: https://vgmrips.net/wiki/Neko_Project_21