The pro may wield any decent cue to knock it out of the park. But amateurs need weight and length matched to their style and wingspan.
I recommend 19.5 to 21 ounces for beginners but under that for intermediates able to work a lighter stick. They (and sometimes me), however, admit we wistfully seek the natural’s stick, carved from a magic tree struck by lightning. Sigh.
When you are better able to manipulate a lighter stick with the hands (to make the shot plus provide outstanding cue ball speed control) go for under 19 ounces…
Experiment if you wish, but realize the difference between the lure of your next new cue and the real magic of practice, competition and drills.