As someone who is about a decade older than the Young twins but who works with teens every day, one thing I can really appreciate about them is their genuine enthusiasm for what they're doing. It's not a new observation, but one thing teen boys often try hard to avoid is the appearance of caring too much. A lot of teen boys (who will grow up to be good, contributing members of society; I'm not trying to dig into them too hard) play up a certain level of sarcasm, cynicism, or too-cool-to-care vibes around guys their own age, OR they tip into a kind of cringey machismo as they try to figure out what "being a man" looks like for them. The Youngs just don't have that same energy; they don't try to play down their enthusiasm or excitement, and they aren't trying to look "edgy" or play up to a more mature audience. I can see how this would turn off guys their own age (and if you read through comments on some of the bigger running IG accounts, there are plenty of high schoolers throwing shade and even subtle homophobia their way), but I like that they don't change what they're doing to fit in.
I'm also impressed by the way they seem to lean into a variety of interests. They have their sport, but they also post about drawing, camping, photography, mountain biking, etc. I wish more of the teen boys I work with had interests outside of their sport, Fortnite, and social media dramas. It relates to the teenage avoidance of "looking like you care," but there's a certain refreshing vulnerability to pursuing a variety of interests. While they might seem weird to other high schoolers, I think in the long run the Young's apparent lack of screen/video game/phone addictions and pursuit of multiple hobbies will be really healthy and serve them well as they grow up.
Anyway, those are just my observations as someone who spends a lot of time around boys their age. I can definitely see why some people would find them "cringe" or awkward, but I also think my students would have better mental health and be better poised for young adulthood if they borrowed certain traits from the Youngs.