For Djing I love to use Mixxx, really solid for mixing and organising music, though I still need a VM with rekordbox if I wanna prepare usbs for club equipment. For music making I like Cardinal which is similar to VCV rack and I do compostion with reaper. Overall the proaudio pacakge group of Arch linux will have most of the stuff you need. For interfaces most class compliant usb interfaces are fine. I control them with qpwpgraph, though I want to try out firewire sometime soon since its legacy and getting reeeeaaaallly cheap second hand

pavucontrol is for pulseaudio which you probably would rather not use when dealing with more professional audio