The other answers address your first concerns very well. As on alternatives to keep files safe from ransomware while still not depending on third party solutions (i.e. cloud hosting):
Get another PC (one with a big storage unit) running a safer OS in your local network, and install a version control software (e.g. Subversion) server.
Commit your files into a working copy, and keep it synched through the version control client.
Subversion would be fine for that, since there won't be many conflicts from concurrent submits. You can script the synch commands to run on a schedule.