This is one of those questions that doesn't have a single answer, but after observing the activity of several channels, I can tell you that the two formats complement each other more than it seems, short videos are unbeatable for quickly gaining new subscribers and getting noticed by the algorithm, a short video can explode overnight, bringing you thousands of views and hundreds of new followers in a week, the problem is that those subscribers who came through short videos don't usually watch your longer videos afterward, they're a different audience. It's as if they live in separate worlds within your channel.
For long term growth, longer videos are still what build a community and real authority, the people who take the time to watch twenty or thirty minutes of your content are the ones who later comment, share, and buy from you, furthermore, longer videos are the ones that rank best on google and generate decent advertising revenue, a short video pays pennies even if it has millions of views, while a ten minute long video with fewer views can earn you several times more money.