Hi Sen (and any others watching),
Speaking as both a 2019 and 2020 SoD mentor, I encourage you to focus on quality over quantity.
Trust is really important in open source projects, and that builds up over time. Your selector needs to take a chance on you. Are you competent? Are you a lateral thinker? Are you prepared to lean into problems rather than passing it off to someone else?
I'm sure you can say that you are good at all those things, but showing me that you can do that is what builds up trust. And the showing takes time. Stepping into a project, assessing their needs, working out how to solve them, showing by tackling a hardish problem which returns real value. All those things will make a very big difference in showing you are trustworthy, and you won't have time to do it for many projects.
All the best and good luck with your application.
Cameron Shorter,
Mentor for The Good Docs Project.
(Note, these opinions are mine, and don't necessarily represent those of the Google Season of Docs team.)