Tomb Raider: Definitive Edition

If your group is finding it hard to find a ranked lobby - try having one person leave the group and search for the same game type. The single person may have better luck starting a lobby which the group then can join.

This seemed to be the case when I stumbled upon a TA group boosting this achievement. Initially, I wasn't in the group and was the host of the lobby when some of the members joined the game type. The rest of the group should get a notification stating there was a lobby found for the group. I then was asked to join/to help boost (and agreed) and then we had trouble finding lobbies unless a random was available as well.

I'm not sure if this is the game mechanic looking for group vs. group really or if the game has a hard time choosing someone from the group to host..

Hope this helps save time for any people/groups going for this achievement....I know the group I joined stated it was going on ~3 hours for them at the end =/

You need a minimum of 4 people. Get yourselves into an Xbox Party and all search for the same game type and if the servers aren't too busy you should all be grouped together. If not you can invite people in. If you keep to the same sides its easier to follow. You need to do 2 games of TDM, Cry for help and Rescue and one game of FFA for each person in the group.
Start a game, and then as soon as you are all in one team should exit the game. The other team will win by default. Repeat for the same mode before moving to the next, obviously the team that backed out first stays in the second time.

For FFA the group need to exit the game except the player that will be the winner. Repeat for everyone and then the Achievement should pop.

You can check the status of the achievement in the TR menu "Feats and Setbacks" which shows what games you need to win. Useful if the achievement doesn't pop for you.

The matchmaking seems a bit ropey on TR so in between each game everyone should back out to the game menu. This seems to ensure that people are finding a lobby quickly.

In order to unlock this achievement you will need a group of four players. Keep in mind that this achievement must be unlocked playing ranked matches. If you are having trouble finding a lobby it involves something with the matchmaking system. Once you finish a match have everyone in the party not only leave the party, but also the game. There should be an option to leave both party and game. If you had no party open, invite all players to a party then choose to leave both party and game. There should not be a problem finding a fresh lobby using this method.

You can also choose to start a match and have one team leave thus forfeiting the win to the opposing team. Rinse and repeat. This will save a lot of time and headache.

Did this achievement in a boosting party recently. Had four people in a party couldn’t find any lobbies. I got the three other people to search for the same mode. I then quit the party, quit to dashboard and closed the game. Restarted the party Re launched the game went straight to multiplayer search ranked which game type we wanted and instantly got into a lobby. May be a one off but happened like this for all the lobbies we needed.

So, as previously mentioned, you'll need a minimum of 4 to start. Now, as a disclaimer, this is just my personal experience, so I hope this is helpful.
I'll just quickly get this outta the way and say the matchmaking is complete ASS. So what my group did was invite everyone to party chat, then we counted down to have us all search and try to sync us up in the same lobby. This usually got a lobby going almost immediately. Anyone missing, I just used "invite everyone to game" from party chat. Despite what people will tell you, inviting people to game has no effect on whether the win will count.
I'm also gonna clear up a big misconception people seem to have about ranked wins.
You DO NOT NEED TO PLAY THROUGH THE ENTIRE MATCH ON ANY MODE for the win to count. You can have all opposing members leave the game. Keep in mind that sometimes the game will bug and continue to play, and it's best to just quickly redo the win.
If you've played all 4 modes and your achievement still hasn't popped, I have 2 suggestions for you.
1) Play through any and all modes you suspect didn't register a win a 2nd time.
2) Delete your save data. The reason for this being your feats and setbacks and multiplayer progress are tied to it.
Hope you guys found this informative. This was my experience from boosting this on both PS4 and Xbox One respectively, and it only took my groups about an hour each with the methods we used.