Anyone found good free HMCC study resources besides the obvious ones?

I've already gone through the standard "HMCC" results on Google and most of it is just selling prep courses. Looking for actual free resources.

What I've tried:
- Practice tests here (solid, especially for HMCC - Healthcare Meeting Compliance Certificate)
- A few YouTube channels but the quality is all over the place
- Reddit threads from 2+ years ago (some outdated)

What I haven't tried yet:
- The official HMCC study guide — is it actually worth reading cover to cover?
- Library resources — anyone actually found useful materials there?
- Specific YouTube channels that cover HMCC exam well

I don't mind paying for something that's genuinely better than free, but I want to max out free options first. Budget is tight.

What resources did you use that you'd actually recommend?