There is a waypoint discord server, a lot of Destiny 2 clans plan raids and use the channels there for chatting. They have channels for both PUBG and Destiny 2 where I’ve seen people find teammates.
I’m on there, but am often too anxious to ask folks if they’d like to game a bit. Though that’s just me, because I’ve only ever seen people be super nice there and I know in my brain that I have nothing to worry.
I don’t know where a link for that is anymore, but I’m sure it’s somewhere if you do a quick search.