I find it helpful to start by looking for hobbies you enjoy for the hell of it and then seeing if there’s a community around that. Making friends seems to be a bit easier when there’s a shared activity to chat about. For example, I took up acoustic guitar and met a lot of people who like to jam together. Also started learning a type of dance and got involved in the community by attending classes and socials. My buddy met his main friend group at a rock climbing gym when he took up bouldering.

For apps/websites, I had luck attending a few Meetups, e.g. like for people learning a foreign language who want to practice with each other. Some people join rec leagues or attend tabletop game nights.

I personally don’t use social media much but it can be useful to see if there are any local events to checkout nearby.