Hyphema

I kinda don't want to level up to Masterclass bass

just out of curiosity for the guitar players here; do you set down your picks/plectrums and actually play finger-picked bass songs with your fingers? if so, bravo - that is a completely different skill than using a pick (and i'll admit i suck at using a pick) I'm not gonna sit here and try and debate the difficulty range of instruments, but each serves a job, and they are not 1:1 comparisons.

I think 6 is fine. With the riff going across all four frets thoroughly, I wouldn't want to rate it lower, because it seems like it would be a challenging intermediate song even though it is not a specifically challenging advanced song.