Friendship is really a matter of time. I found this article:
https://news.ku.edu/2018/03/06/study-reveals-number-hours-it-takes-make-friend. Here's a quote from it:
In a new report published in the Journal of Social and Personal Relationships, Associate Professor of Communication Studies Jeffrey Hall found that it takes roughly 50 hours of time together to move from mere acquaintance to casual friend, 90 hours to go from that stage to simple friend status and more than 200 hours before you can consider someone your close friend.
You really need to put in the time time. To make a casual friend, you gotta spend 50 hours together. To be simply friends, it's 90 hours. To be considered a close friend it usually takes at least 200 hours. Of course friendship isn't math, but it's an important principle. The trick is then to first find people that you're interested in spending that much time with.