For SEQ files it's actually really easy. In fact SEQ files are almost identical to MIDI files as they both use the same OP codes(!) It's possible to convert between one and the other back'n'forth almost without losing data (the only data you lose is loop pointers and NRPN data, but those can be rebuilt easily).
SEQ is a "sequenced" audio format, similar in nature to MIDI.
This outstanding post says converting SEQ to MIDI is quite doable. https://www.reddit.com/r/OsamuSato/comments/snzrfu/sato_videogame_soundtracks_reworked_and_exported/
Related #36