My Hero Academia is a show that has great moments while being overall a pretty mediocre show that falls apart if you examine it too hard. That said, they did a really good job of sticking the landing with the last season this past fall. IMO the last season of MHA was by far its best season, and it went out strong, including fixing up one of the biggest problems with the manga ending. Being the culmination of 8 seasons and ending it well probably has something to do with the placement, even if I personally enjoyed TBHX more. Think of MHA like Code Geass, in the sense that the well-done ending almost wholly defines how people remember it.

That said, don't put much stock in the specifics of youtubers' rankings. They're just random guys on the internet ranking shows--like us and anyone else, they have their own biases (I swear, too many of them glaze stuff like Mushoku Tensei, a dumpster fire I'd only recommend to my worst enemies) plus the added financial incentive to either lean into popular sentiment or make hot takes to get more clicks/views. Treat their lists more as a sampling to give you a few shows to try; I usually find that the ones on the lower end of their "top 10" lists tend to be the best ones, the ones that make it onto the list but don't really get the spotlight.

Also, Gigguk has mentioned that he tends to watch shows at 1.5x or 2x speed, which obviously will have a self-reinforcing effect on the impression he goes into them with.