Turns out I have a strict NAT, this appears to be an issue in this game despite it never having been one in other online games. I also have a private IP address so port forwarding doesn't work. https://help.bungie.net/hc/en-us/articles/360049496751-Advanced-Troubleshooting-UPnP-Port-Forwarding-and-NAT-Types (I've also already tried everything recommended on this page) On this page it states that I should still be able to play with people who have an open NAT, but the game is completely empty for me. No one in the tower or other open areas, can't find anyone through matchmaking.
Again, all other multiplayer games work without issue, I don't get disconnects, my ping is low, matchmaking is fast. I've been trying to fix this for 2 days and have tried everything within reason, someone tell me I'm not alone with this.