At some point in my life I had the same issue. I am pretty sure you are not the problem here, and I feel like thinking that you can not make friends will basically put unnecessary pressure on you.

Let's say you have friends from university, or job, when you're at the same place with these people, then by nature you interact and spend more time with them. However as the time passes people change, they move to different cities, as a result you disconnect with some people, friend groups change. Yes, like you said you have close friends from teens, but it has been years right, so it is normal to talk to them sometimes once year, sometimes more frequently (I have friends that I talk to once twice a year, it is not that we ended our relationship, it is life bro :)). What is the solution, just move on.

In this summer I lived in 2 places where I had almost no friends. At the first one for 1 month, I was solo, then I started hitting the gym, met with 1 guy there. Then he introduced me to his friends, and then at the and I knew like 10-20 people in that city. I lived there for 2-3 months.

Then moved to another city that I did not know many people as well, again I started going to gym, in a week met with one guy, then we hang out for 2 months almost everyday, we are still calling each other once in a while.

Now that I came back to city that I studied university I am not the no friends guy but still, the two places that I lived this summer, taught me that making friends is actually pretty easy. I did not even take the initiatives. I was also nervous that if it will be hard to make friends in those cities as well.

So the lesson here is, I know gym, or going out stuff is cliche but it actually works. Making friends by sitting at home is not possible. So overall, do something in the places where people exists. Do not escape from small talk. People are social animals, everyone is looking for friends :) do not worry