i've got a simple per-project dot file that describes the file system binds. while i'm working on a project, new terminals i open are automatically isolated to that project based on that dot file. it has very low (cognitive) overhead and integrates pretty much seamlessly. i suspect many developers have similar scripts. i looked for projects that did this some time ago, but couldn't find it. either because it's too simple to make a project about, or because i don't know how others would describe it. if anyone has pointers...
i don't limit network access (though i did experiment with logging all traffic, and automatically setting up a mitm proxy for all traffic; it wasn't convenient enough to use as regular user). there is still a whole kernel attack surface of course. though i'm mostly concerned about files being read/destroyed.