Answers
When do couriers get paid?
Weekly, through Stripe, for network jobs. Commission and any deductions are broken out per delivery. Work done on shift is paid by the restaurant the courier is attached to, on that restaurant's own terms. A courier who does both sees the two separately.
In more detail
Every deduction is itemised per delivery rather than rolled into one figure. A deduction discovered after the fact costs more trust than an unattractive one shown up front, so commission appears at its real size on each job before it is accepted.
The two modes stay visibly separate in the app, because they are different arrangements with different payers. A courier who works your shifts and takes network jobs between them can see which money came from where.