The issue is simple: Since the originally smallest commercial utility engine used to be 23 cc there never was much development in carbs for smaller engines.
And a 26 cc fourstroke twin requires a totally different carb than a 2-stroke single of the same displacement.

In all fairness, MMM's hardware is pretty good: Very well fitting brackets and rings, and very well made carb adapters.
But either his carb selection totally sucks, or his supply is inconsistent and he slaps on whatever he can get, I don't know. Fact is, if you watch his YT vids on a large screen and half speed, you will notice a very inconsistent throttle response that (deliberately or not) is hidden by manipulating the throttle such that the engine sounds as if it responds excellent. Only if you pay close attention, you will see that engine response not always matches throttle movement.

It is one of the things I lately at least TRY to get very unambiguous into my videos.