My advice is to try AC Pro. Relatively inexpensive, just make sure to add the refrigerant slowly and check, following the instructions on their YouTube videos. I can get down to the low 40's from my vents with the needle just to the right of middle in the green section on its built-in gauge.

More info in this post:

https://xoutpost.com/bmw-sav-forums/...y-2-vents.html

I've been using it for four or five years now. This year with the high-mileage sealant version.