Since there is an entire AI community[0], claiming 135,000 members, that labels themselves 'tinkerers', any pejorative meaning in tinkerer is long gone. Probably in the same way as 'hacker' was once a rather pejorative term to the general public.
You would not want a surgeon who says that they’ve tinkered around with surgery. You would not want a pilot who says they’re tinkered around with piloting.
Synonyms are quite literally beginner; dilettante; novice; pretender; uninitiate.
For example from the original analogy, if you told an entrepreneur that because they didn’t use AI, they were not an entrepreneur, but instead “unskilled” or a “beginner”, that would be disparaging; pejorative.