According to its inventor, Scrum™ was created to manage a team of dysfunctional COBOL programmers at a bank[1], not to find a Product/Market Fit (PM/F).
Instead of using an SDLC methodology here, use one of the relevant product frameworks for that, but needless to say, there is a large element of luck here, as finding a PM/F isn't guaranteed.
Usually you use low-tech SDLCs like Scrum/SAFe at the places that already have found PM/F, or those relying on violence (aka "taxation") as their main business model (e.g. military/government/public sector).
The only PM/F Scrum Inc found is how to make bazillions from useless certifications and training.