I have helped clients recently where they wanted to change their business venture entirely, and even those who wanted to switch endorsing bodies.
If you do so, then this would likely (in most cases) to entail an extension. The change would be indicated when you extend. There is a section in the extension endorsement letter covering this:
But you could, after that, apply for settlement. You would be judged against the second business plan rather than the first (both by the Home Office and by the endorsing body).
So, I have helped people switch endorsing body and apply afresh for the Innovator Founder visa. This does trigger an enquiry into what your achievements were under the first business plan. In the case I dealt with most recently, that was fine. I had not worked with him for his first visa application. He came to me when some challenges had some up. So I helped him start afresh, with a new endorsing body, on the Innovator Founder visa.
Now, prevention is always better than cure. The original business plan should ideally not be too narrow and linked to a single product idea which is super specific. Some of my clients have mixed consultancy and product businesses, where the product is closely linked with the consultancy offering. This is one way of achieving sufficient flexibility to ensure you avoid having to switch later on.