This is a fascinating and insightful comparison. I learned many things here. Both genres emphasize virtuoso pyrotechnics. Here's an extended banjo jam by Don Reno that really shreds the strings. https://youtu.be/pF5OPyu59m0

There's a 1949 song by J. E. Mainer's Mountaineers that is pure mayhem--unfortunately it's not on YouTube, but it's on Amazon and may be on other streaming services (I keep intending to post it on YouTube and write a piece about it here). It's called "Shoot the Turkey Buzzard." Mainer recorded a later version (which is available on YouTube) but it's polite and not that interesting.

The flip side of the original is on YouTube, and is closer to the anarchy of the original, but still no cigar. https://youtu.be/woHj1JLzO2I

I'm not very knowledgeable about metal, but I respect the genre; my taste runs more to the mashup of lounge music and metal by the group Hellsongs: https://youtu.be/TUz9fLDAFHU