I wonder if Spleeter is related to https://github.com/wslihgt/separateLeadStereo
This thread has some examples / comparisons for the latter: https://forum.audacityteam.org/t/reduce-voice-not-eliminate/45504/1
It might be interesting to see / hear comparisons between Spleeter and separateLeadStereo.
Spleeter is available as an online app, e.g. … https://moises.ai/
IMO, either the instrumental (karaoke) version, or the isolated-vocals, are useable, but not both.