Me and MY Friend in RL figured out how to "party" cross platform on PC and PS4 (Sorta)
So I'm a PC user and my friend brought his PS4 over to my house. We were lamenting about how we wished we could play fall guys together. I came up with a zany idea that maybe if we both started up the game and choose the same show and server region (we went with US east) and clicked "READY" at the exact same time on both of our games we might get put in the same game.
Low and behold about 90% of the time it WORKED! Worked amazingly actually, our screens were in perfect sync as the game was searching for players (the player numbers being counted on both our screens were in complete sync) not only that, but we would be on the same team about 50% of the time. We had a lot of fun and won about 4 crowns each last night.
I don't know if this would work if we weren't using the same internet. (we were both hard wired into the same router) so I don't know if you could sync with a friend over the phone for instance, but I still think it was a pretty cool discovery!