pve matchmaking does not work properly. Especially when you play with one other friend on ps5. No one joins into your session no matter what you are doing. For single players I have found an workaround if you can’t find matches with other players:


Go to the terminal, go over to PvP multiplayer just hit the circle button so you go into the PvP mode. Now choose an mode, doesn’t matter which one, when you find a match with other players, go back and switch over to pve, again just go to the terminal move over to the pve tab and hit the circle button, don’t choose or click an actual mission. When you in the pve area now you can choose an mission and you should find other players. 

but as I said in the beginning this does only work if you are alone, if you already have on other players you can’t fill up on a third player right now.