I don't know if 99.9% of the people that post here are on XB Series S/X or PS5 or in North-America, and if this isn't an issue for them, but this latest update (the week leading up to Christmas) has KILLED (3on3) drop-in matchmaking on PS4 (and presumably XB1) in Europe!
We are searching 10-15 times and regularly more than that to find a game! And it's not a matter of there not being potential opponents, there are... it's just not matching up against them for some extremely dumb reason.
It was good until this latest update and some terrible change has now killed it.