This is very easy advice to give and oft repeated, but I’m deeply skeptical that this is something that works for most people (unless we substitute friends with acquaintances).
Isn't that the case for 'work friends' too? The people we never see or hear from again the moment they get a good offer at some other company or we ourselves move on to other roles? There will be exceptions of course, people you meet at work who you actually form real meaningful connections with, but there will also be exceptions for the people you meet while volunteering, or while playing a sport. Either way, most of the people in our lives are strangers or acquaintances.
My board game buddies are my closest real life friends, and I met them exactly like this.
However people do need to accept that not everyone makes friends the same way.
I’m just going anecdotal here from college friends that have dispersed across the US.
Warm intros, so to speak, help. If you join a running group attended by a friend of a friend it seems to stick better than joining when you know absolutely no one.
Public transit helps. It’s hard to be consistent when going to the activity requires slogging through traffic.
And lastly, an activity that encourages repeated regular attendance. Hiking is an activity that is super flaky attendance compared to say training for a triathlon with a specific event day.
Most people meeting over other activities I believe have similar stories. Dancing for example, or other group sports.
I've made some very good friends since leaving university. The simplest thing to do is to start with something YOU enjoy. Food, sports, music, pottery, knitting, boardgames even coding (gasp but that's our work).
If you have a passion and you want to be there, and so do the other people - the odds are in your favour that you'll get along.
You have to get out there. The Internet is not a great place to form solid human relationships.