There is a Discord server that has neighborhood 'channels', the Heights channel is pretty active. People coordinate planned meetups and also 'short notice' walks, activities, lunches, etc. The larger server also has a book club, a brewing club, a walking/hiking and climbing group, etc etc. Sports are less active but I've seen general interest in pickup basketball, tennis, etc. so someone just has to make it happen.

Permalink invite: https://discord.gg/uESAxjEeHh

I guess it's kind of annoying to have to join yet another social platform but once you accept the basic rules and understand how to navigate the platform, it becomes fairly easy to coordinate and join activities.