Mise uses asdf, which heavily relies on shims. But you are saying that mise does not use shims?
It's even said almost at the top of the README.md in the "30 seconds demo" section:
"The following shows using mise to install different versions of node. Note that calling which node gives us a real path to node, not a shim."
https://github.com/jdx/mise?tab=readme-ov-file#30-second-dem...
So yes, mise does not use shims. It only manipulates $PATH. I did benchmarks a while ago and that definitely and consistently has shaved some milliseconds off of the startup times of my tools.