fiddle~ and sigmund~ are the max objects you’d use to make something like this in Max for Live.
The Helmholz device looks like it uses its own custom external (no info on the website, and the patch is definitely not set up to be easy to understand by other people), so I can’t speak to what it uses under the hood.
One could hypothetically take the CV Envelope Follower patch from CV Tools and modify it to use fiddle or sigmund to make a CV Pitch Follower
bonk~ would also be a good one to look at if you want transient detection (i.e. send a gate high whenever there’s a new note played)