There is a clear situation in Foss( even more in self hosting) where projects are presented as free open source but they are intended to monetize at the end and use the community help for development.

What would be the best foss for Android ?

Never used I2P before because of slowness fear I got from Tor network and from the attempts I did and saw that awful Java client. But your approach made me interested again. Once connected there, how to reach content? Like downloading stuff and dig into what ot has to offer?