If you're allowed to rent the car for gig work, they'll almost assuredly offer the insurance for it, and not all gig work is ride share.
Depreciation, maintenance, those are lumped into the cost of the rental.
And the duh was about that, I handled the insurance comment separately.
edit: e.g
https://www.hertz.com/rentacar/misc/index.jsp?targetPage=delivery_rentals.jsp
They offer the rental and insurance. They don't let you carry another person though, so not all gig work, at least on this specific plan.