I don't know either, I've been working on this topic for 5 years now...
I've tried making friends through work, tried Bumble BFF, tried Boo, tried checking MeetUp, went to events on things I like, lowered my standards for friends - after all that, I don't have much to show for it.
On Bumble BFF made one superficial relationship with a girl who I honestly don't like that much. More than a year of "friendship" later and I'm just wishing she forgets about me. This all happened because people kept telling me I should try to hang out with people different to me, people that like going outside, bla bla, and so I did.
Another girl was also through Bumble BFF, things were going well, we even spoke the same language but then she bought a house in another city and ghosted me.
There were two other girls but things ended pretty quickly as well with either ghosting or one of them saying to my face that I was too sad to be with. This is when I had decided to not pretend and be honest.
My psychologist always mentioned that I needed to go to an event or something and make friends that way. Yesterday I went to a very niche and small event, for a topic that I love - I don't know how it's possible to make friends at events because people don't talk to me and I don't know how to approach them either without being a creep! I actually spoke a lot with vendors and people from a rescue there, even asked another customer where they had bought their shirt. Got my answer and they went on to another stall. How does one make friends irl, I have no clue, I don't think it is possible.
All of this oversharing and rambling to say: you're not alone, it is hard as hell and I so wish I knew how to help you but I've tried so hard and got so far and in the end, it doesn't even matter.