

There’s more than this required to build anything that’d be needed to survive in an automotive environment, and considerably more if you are hoping to have an open source/FOSS design that would be accepted as a suitable replacement for something proprietary, although I don’t think that was your aim (but it does sound like OP’s). I’m all for grassroots/homebrew stuff but we’re talking about a thousand kilos+ of steel and plastic being hurled down a road carrying people, in and around other people in similar contraptions. This isn’t something I’d exactly condone throwing a hackerspace’s resources and some Arduinos at.

Syncthing (distributed folder sharing including “keep x copies of each file”) and duplicity (gpg-encrypted, incremental backup anywhere) are your friends.
Been using them for a very, very long time. A++ open source, cross-platform solutions.