How much commission to charge for a new marketplace? I will not promote.

Hi everyone, I’m building a B2B/B2C marketplace in a niche services industry where service providers can create profiles, offer their services, and customers can book and pay for services through the platform. I’m a solo founder and currently handling everything myself. I’m trying to figure out the right commission structure. The platform uses Stripe connect for payments, so there’s already a payment processing cost of roughly 5-6% per transaction before I earn anything. My challenge is finding a commission