Stripe connect - holding payment

Hello Stripe Dev Community! I have the following question:

We use Stripe Connect (Express Account). Our payment process is like this: Customer pays, payment gets on hold, service provider provides his service, after confirmation through the customer, the payment gets released.

Now our questions: 1) How long can we hold the payment? 2) Where does the money "sit" until we release the payment? 3) Do we have somehow access / influence to this money during the process? (because this can mean legal issues)

Thank you in advance!