I am 47. Contemplating to close my office and go to work full-time as a design->frontend person for big corporation. Ageism is real, but I see it as a use-case

I am 47. Contemplating to close my office and go to work full-time as a design->frontend person for big corporation. Ageism is real, but I see it as a use-case experience. If a company cannot utilize my professional experience as ex owner of business, PM or design specialist in general, it means that they prioritize "cultural fit" criteria over real performance evaluation. This is not a problem for me. I don't have expectations every business to be "mature enough" to know the value of effective professional work over "power of the young mind". The idea that after "40" you are having "cognitive difficulties" or you are "out of fashion" comes from companies who exploit trough "overtime" or extreme performance prerequisite. Working in this kind of environments is a suicide. Burnout is real and avoiding it is the only effective countermeasure.