[lewo]

> would be hard to beat "sync a file to a warm container and run it"

It depends on the size of your Pex file (i don't think you mentioned it and sorry if i missed the info). With a Docker/OCI image, it would be possible to create a layer with only the Python files of your application (without deps and interpreter). (I say "would be possible" because that's currently not easy to achieve with Nix for instance.)