They aren't. Like I keep seeing this brought up and it's just easily verifiable by going into the battlepass and seeing that there are options in the premium that just are not available elsewhere. Like sure, the game is on the fair side of "P2W" but the fact remains you can immediately pay to start unlocking more varied weapons, while someone on the F2P path first has to grind out the SC's to do so.
There is no solution because the system isn't designed for the number of players on the game. So your only option is to either host your own game (and let the other scrubs join you) or just keep spamming the QP button until you get into a group (you are essentially, as I understand it, competing with others for available groups so that's why you're getting the failed and why it isn't consistently - could be 10 tries could be 1, all depends on the number of people trying for that exact group that the game says is available).
. . .their SNOWRUNNER video is one of the greatest examples of "This Game Is Terrible Because I'm A Terrible Gamer" you'll ever see. The comments dragging them were also fantastic if I recall.