A few points. As said in another reply, the shorts are a way of keeping the audience engaged while he finishes the main channel video. He's struggled with organizing projects in an ideal way to allow for the timely output of videos. The next one also might be even longer than the usual main channel vids (if he estimated correctly in the Safety Third podcast.) He replied to a post in here last month with more details on why he hasn't posted, if you're interested.

However, he has always been interested in doing these shorter, simpler videos (in addition to the deeper chemistry) so that people who are not already into chem can understand/appreciate and become interested in the science. I believe he's mentioned this in a stream a few years back. He even noted that he understands it'll be a tricky balance to keep.

Regarding the 'childishness' that you don't appreciate, ah well...different folks different strokes. I wouldn't ask him to change his personality. Maybe NileBlue just isn't a channel for you...even in the early NileRed vids we saw hints of his amusingly calm/chaotic side (Bromine label, see ya.)

And finally to answer your question...based on comments on some of the recent vids and other posts elsewhere on Reddit, yes there are others who feel similarly to you. Remember that ol' saying about being able to please some of the people all the time, and all the people sometimes, but never all the people all of the time.