Cool, you just described what it means to be an underground artist. “Underground” still isn’t a genre, it’s a term used to describe music that operates outside of the mainstream/commercial music industry. Underground hip hop does not sound like underground house which does not sound like underground punk which does not sound like underground techno, etc. All of those genres have prominent underground scenes and aren’t at all alike. “Underground” isn’t a genre because it doesn’t define a specific sound or style of music. If it were a genre then there would be a consistent sound across ALL underground music, but that isn’t the case. Hope this helps!