I feel the same with my friends from school but the reason we feel like that is that school forced us to be together and a deep friendship was forged as a result.
In adulthood, that forcing function doesn't exist so you have to make the effort. So regardless of whether or not it "feels natural" to go "friend-hunting" (it doesn't to me either), if you don't do it, you will be without friends.
It's also worth framing it to yourself differently. Friend hunting sounds awful and fake but organising fun/activities for similarly minded people seems more positive
In adulthood, that forcing function doesn't exist so you have to make the effort. So regardless of whether or not it "feels natural" to go "friend-hunting" (it doesn't to me either), if you don't do it, you will be without friends.
It's also worth framing it to yourself differently. Friend hunting sounds awful and fake but organising fun/activities for similarly minded people seems more positive