Craftify 1.19.4 does not work with Cider 1.6.0. Playing a song using Cider 1.6.0 does not display anything in Minecraft with Craftify 1.8.0. However, using Cider 1.5.9 seems to solve the issue. I'm assuming something's changed with Cider 1.6.0 which is the source of the issue.

I've tested this and had it work possibly another issue is at play here.