SEO boost for titles, tags, description and so forth primarily impact a video earlier on its life. YouTube fills things in and reweights as it gets actual watch time data, so this explains how ultimately, videos with high numbers of views but bad seo can still rank high.
I looked at your channels bean boozled description (I can't see tags from my phone) and it seemed to me that you have a very minimal description that doesn't reinforce your title (for example, you never say the exact phrase "bean boozled challenge" in the description, when we would expect that if this were a targeted keyword, you'd try to mention it several times in the description.
Also, it could be that this keyword is too competitive. If I search for your exact title, your video is on page one... But would anyone put "kid's surprise"? Maybe you want to target the keyword " bean boozled challenge for kids" with that phrase reinforced in title, tags, and description.