That video was not that bad. The thing for me when it comes to reaction videos is that they have to have some funny commentary or funny bits. I would say work on your commentary a little. Look up ways how to be funny such as irony, self deprecation, double entendres, puns, satire, exaggerations, etc. Implement these and do more editting to your videos and I would say you have some solid potential.
As for bits, I liked how you commented, "the delete your channel challenge". So maybe you can incorporate that into more of your videos and that can be your "bit".
To be honest I didn't think I would laugh because when I saw you were a kid, i was like "welp here we go again. The funniest parts were "we were 2 subscribers away from a million" and "the delete your channel challenge". That's where I actually laughed because that's comedy i.e. irony and originality which goes along the list I said above.
Oh and cut the video shorter too. Like don't play the whole video. Only play parts where you actually comment on things. It'll keep people engaged longer.