It's probably "My Flag Design Process, Step by Step".

The topic is broad enough to have fairly general appeal, but especially appeals to the niche my channel caters to. It's insightful, but presented with a decent amount of humor (although I still feel like my videos aren't funny enough).

The video is the perfect length: Long enough for me to get into some detail, but short enough for it to hold people's attention.

The editing isn't perfect — my later videos are edited better — but the editing is still reasonably good.

The microphone quality is good, audio mixing is decent but not perfect.

The visuals and music have an aesthetic close to what I want my channel's aesthetic to be.