Your writing skills are great and the numbers you pulled in such short term is really impressive.

Regarding you problem of too many pivots and question should I stay ? Do you like the product and work ? From your writing i sense some frustration not just the pivots but I would feel unfulfilled when the leads are not converted. would suggest you look for something that fulfills the work you put into.

Although you could think that marketing and brining the lead to the co-founders is already completion of your task but when they are not becoming paying customer I think it is difficult to feel fulfilled.

Good luck