Lemnis Gate

This achievement will take around 10-20 mins using this method

Setup: you will need a boosting partner or another Xbox/pc, personally I used Xbox + pc to do this.
Next your going to want to get matched in the same game using a matchmaking code which you will see at the bottom of the screen when you hit play on the main menu so just search for any 1v1 mode using the SAME code it can be anything I just used the letter "Y" and always got matched instantly

Method: once your in the game

Player 1: Hit start and concede match then as soon as defeat pops up hit A then press start again and this time hit "request restart"

Player 2: then the other player needs to do the same and hit "A" on the victory screen and pause and request restart

Doing this it will keep restarting the match so you can get a game played every few seconds once you got the rhythm down

One thing to note make sure you have voted to restart on one of the accounts before the other one presses A to continue otherwise it will put you in a new game which will just take longer

Any question please ask away hope this helps someone :)