Do you really mean a monorepo, though, or just a project repo whose scope is one entire game? Because a monorepo for multiple games - including released and in progress ones - seems likely to create a lot of pain in the long term. The release cycle for games seems much more suited to a release branch model, which would kind of require per-game repositories, and some sort of package versioning for common dependencies. I guess maybe with things like mobile games where you have a constantly moving target platform even ‘released’ games are live code so maybe I’m just betraying an outdated ‘gold master’ kind of mindset here?