Instead of partitioning, MacOS let’s you create volumes, which are logical only, not physical.

I have everything on my internal SSD, but created a separate volume for my music/audio projects. Volume size is elastic, so the OS can allocate more to one or the other as needed.

My VI libraries are all on MacHD (or C: drive in Windows speak).
I think with current SSD speeds, there is little point in keeping everything separate.