This is a solved problem with git. I’ve worked on bigger projects than yours with histories that are so big you can’t clone them if you wanted to. I’ll make a note to drop what to google for tomorrow, but basically the history is fully available but git knows how to query it over the network. When you open a file, it loads it over the network. Remote build systems do your builds.
Most of this was built by Microsoft to work on Windows with git.
We moved from SVN in the late 2010’s, and holy crap man, did it change our workflows. No longer were we passing around patch files in a team for code reviews, but actually reviewing code somewhat like on GitHub. It was magical.
