It was so easy to make friends during my undergrad because I lived in the dorms. But I lost half of them due to a messy situation with my ex girlfriend, and the other half doesn't live in town anymore.
Now I'm 22, working on my Master's, and I feel like I have no one.
Outside of university I'm active in several groups related to activism and civil rights and have met a lot of people I'd consider to be genuine friends. It is also possible to make friends online if you know where to look. Could be possible to start a niche discord/revolt/matrix server related to something that interests you and try to make friends that way. I find that having 10-20 active users in a server is the golden number for making online friends.