Them being nonprofit has nothing to do with the pursuit of marketshare. Plenty of nonprofits want to maximize marketshare. Them being nonprofit means they are mission-driven.
And what is that mission?
Per the Signal Foundation's website:
Protect free expression and enable secure global communication through open source privacy technology.
A lot of these recommendations are for advanced gamers.
Some more entry level games include Portal and journey.
Slay the spire is also excellent if you like card games.