Has anyone checked out SPLEETER? I started using it recently for making all my own backing tracks to play with (in Go Play Along). But it would work great for CDLC too!
https://research.deezer.com/projects/spleeter.html
You can extract out all the tracks, then using audacity, create a backing track with just DRUMS and VOCALS. It was hit or miss until version 1.54, but now its solid and does an amazing job with the tracks. They released a video on how to do it here a while back, but it still works the same: