The easiest way to make new friends is to be around people in social settings where you have the opportunity to find someone who clicks with your preferred way of communicating. A dedicated ADHD group may or may not work, but it would be a possibility.

I haven't made new friends for decades because the small group I have filtered down to the current group because we stayed in touch. I have had opportunities, but nobody else has clicked or been a good fit to loop in. Occasionally we have new people join in and fade out. I am not the one who adds to the group because my ADHD works well with about four other people.

Can't imagine starting over somewhere new without knowing someone already.