From what I’ve heard of seen in the Linux community music production on Linux is not easy. There is a fair amount of tweaking to get audio working and connecting instruments.

I’ve once created a profile with about 1500 lines of code for powershell, managing AD at work. It was great to learn, it’s great for scripting and it’s very intuitive (for me at least), I also liked working with objects.
I wouldn’t use it on Linux though, I’m not sure how well integrated it is.
I’m using fish at the moment, desktop and server, and I like it primarily for the functions and the autocomplete

As others have commented, stick with the Mac.
I recommend installing proxmox on it and run the apps you want. You can run pihole in a VM.
Do you need a NAS? Not really, but if you have cash available maybe get a used tower, use the disks you have and install TrueNAS. And this will only cost you max €200