Override Base folder via commandline flag

If I am working on multiple projects, I would like to have multiple BASE directories.
I start ComfyUI.exe with some flag to the new base directory.
This way I can start with a clean installation that does not use 100GB of models or custom nodes from the old project.

I know there is --extra-model-paths-config, but this does not work.
It still loads stuff from the old BASE directory.
If I open a workflow and it asks me to download models, they are saved in the old BASE directory.
I cannot share my new model folder with some other machine else as I never know if it provides all files required.

And it would be nice to set the python venv directory as well.
With a commandline flag, not an env var.
As it is part of the BASE directory right now.
But from a development perspective it is part of the application, not part of any workflow/user data. Therefore I would like to move it into the app folder.