I am not sure what you are trying to say exactly, however the re-certification that should be required for the 737-MAX was exactly the reason for introducing the MCAS software to prevent the crew certified for older 737 models from pushing the nose into the ground on take-off. That, together with glossing over the major design change so that no pilot would flag “hey, this is a new plane, we should get a proper new certification for this” contributed to the two crashes, murdering 350something people over profit.
Boeing wanted to sell a new plane model with significantly altered aerodynamic behavior as a “variant” of an existing one so airlines could save cost on not having to re-certify pilots.