Have you checked Calendly? I’ve been using Calendly for scheduling for a while and it’s awesome.
Plus calendly also has this feature where you can charge someone for scheduling a meeting. Though you might need to get a paid subscription for it.
If you really need a custom solution, Stripe and Google Calendar API can do the work for you (or you can also use Calendly API and Stripe). Totally depends on the overall idea you wanna build.
Happy to help if needed. Feel free to drop me a message. I own a development firm and we built Web Apps, Mobile Apps & SaaS products for clients
Calendly’s paid version can sync multiple calendars. Though I am not sure if it can also block slots on all of those synced calendars as well. You might need to custom build that functionality