You should be using build artifacts, not relying on `uv run` to install packages on the fly. Besides the massive security risk, it also means that you're dependent on a bunch of external infrastructure every time you launch. PyPI going down should not bring down your systems.
There are so many advantages to deployable artifacts, including audibility and fast roll-back. Also you can block so many risky endpoints from your compute outbound networks, which means even if you are compromised, it doesn't do the attacker any good if their C&C is not allow listed.
This is the right answer. Unfortunately, this is very rarely practiced.
More strangely (to me), this is often addressed by adding loads of fallible/partial caching (in e.g. CICD or deployment infrastructure) for package managers rather than building and publishing temporary/per-user/per-feature ephemeral packages for dev/testing to an internal registry. Since the latter's usually less complex and more reliable, it's odd that it's so rarely practiced.