what are the advantages of using pipenv sync over pipenv install?
From looking at the docs, it looks like pipenv install will install all dependencies from the pipfile, and update pipfile.lock with the versions it used. pipenv sync will install the exact versions specified in pipfile.lock.
I would say sync is better for getting your environment to match what is checked in, and install is for when you want to get the latest versions, or are adding new dependencies that aren't in the lock file yet.