Sounds like you're confident you (or the FOSS community collective) can spot cleverly hidden backdoors.

I'm not, and I find that position naieve. For the overwhelming majority of people who are not a cross between Bruce Schneier and Linus Torvalds, a threat model that tries to protect against the NSA and GRU and MSS pretty much requires avoiding anything with a network connection. If you have a smartphone, you should probably just use its default application store.