It might be a lucrative deal for your vehicle and trim but might want to check your lease paperwork again. In my Chrysler lease contract there is a section states “you will not sublease the vehicle, assign, pledge or permit a security interest to be created in, or in any other way transfer your interest or responsibilities in the vehicle and in this lease”. It’s vague at best, best technically Turo is a short term lease.
In the event of an accident, even if your insurance paid out, GM could deny gap coverage since you broke the contract.
IMO the minimal monetary gain is not worth the risk, maintenance cost and headache.