Hmmm... I’d like to think this through.
How many generations of mammals has there been in total since the first mammal ?
All evolution necessary to go from that first mammal to us humans today would have to occur in that many generations.
I don't have any idea. It would be tough to know since the arrival of mammals is estimated within a block of several million years, so whatever hypothesis you came up with could be off by that factor.
Remember, the theory of evolution explains the fact of evolution, just like the theory of gravity and general relativity explain the fact of gravity.
We know evolution is fact, we're just trying to come up with the best theoretical mechanism for how it works, just like we look at gravity and know its fact, and we accept Einstein's theory as the best explanation.