How to get 149 gems in 7 days?

As everyone knows, Stu's hypercharge is coming out in the next update. As a Stu main, I need the hypercharge pack, with the hypercharge and the cool profile icon. The only problem - I have only 19 gems, and I cant get gems from the brawl pass since I completed it, also I'm F2p. Is there any other way to get gems fast?