It seems a lot faster than pipenv.
From the little I've tried, it seems a lot more sane - but I'm biased - I hated pipenv and never saw the point of it.
It used to be incredibly slow but these days I find it's not so bad. It even has parallel pip installs now which while occasionally triggering some issues in projects with over complicated setup.pys is usually a lot faster than a good old pip install -r requirements.txt.
So have you considered the possibility that it may not be the fault of these package managers, but that there may be a different problem underneath it all that a package manager cannot fix for you?