Bug bounties work by: You tell them what the bug is, they pay you money if it's real and dangerous. It's not a way for you to blackmail companies by threatening to give it to the dark web. That's a sure fire way to get lawyers involved.

The way you are asking mommy/daddy/uncle/aunty for who will pay more for your bug indicates you are not a trustworthy person and are not interested in doing the right thing. These companies will naturally not want to do business with you because you are not acting professionally.