I worked in a big bank in the UK using monorepo "cuz Google uses it", error number 1, your not Google. The clones were gigantic, Jenkins would timeout cloning the whole project when all it needed was a bunch of files. Merge conflicts all over the place, but the best part, we had scripts on our pipeline literally removing folders after cloning the repo to avoid automatic inclusions of libs etc. In my opinion separation of boundaries is one of those things that should t be mess with.