When I go to a GitHub as a hiring manager, I try to get as much signal as I can. You are scared that I'll solely judge you on the code, but I'm looking for metadata. Is this person interested in or exploring problems/technologies that are related to the problems/technologies we are using here? Oh, They are exclusively doing music based coding? INTERESTING. Let's talk about that in the interview.
Oh, They've contributed a bug report to an open source project, lemme see what that looks like. Nice, repro steps are clear.
And yes, some hiring managers are gonna say "welp, this candidate isn't an open source ninja so we don't want them." But that's not all hiring managers.
What is a big turn off for me personally is the "I'm gonna slap something on github to tick the box" group. I had someone submit a resume with a link to their website and a link to their github. The website was literally just a demo site, but they had changed all of the blog titles so it looked like real posts, but if you clicked through, it was all lorem ipsum. The GitHub was also just the code for this site.
I'll take a graveyard of personal exploration everyday over a half-baked sham site. (Note: They could have just been playing around BUT TELL ME THAT! Because it sure looked like an attempt to look the part.)