Join a lot of tournaments with the lowest time limit possible.
Make sure the tournaments are 4 people only, so you can quickly finish them.
Fill the queue and for any tournament where you're not first, you'll want to leave and wait a bit before queuing again. If you're the second to make the move, the timer will start to count as soon as you've made it, no matter if your opponent is in the game.
Wait a few minutes, claim the win, and hope you'll be 2nd to move in the 2nd match as well. If that's the case, you win that as well, otherwise, just hope you'll be at the PC when the opponent makes their move.
Just repeat this until you have won all of the tournaments - It might take ~2 weeks if you check it 2 times a day.
Alternatively, you can make a few alts using steam family share, and boost yourself using those. The only problem is that it is a lot more work for you, but you will finish everything in a few minutes.