A  few months ago, I moved from a windows host to a Linux host (and I tried various distros... Ubuntu Studio, Debian 13, AV Linux, MX Linux, Linux Mint...) and had the best experience with MX Linux 25 (now 25.1) with KDE desktop, systemd, 64 bit.  Initially, I had hopes of using AV Linux (or similar "re-spin") already customized for audio.  However, although I didn't have any problem using AV Linux in a VM, where I could use Windows Host Drivers, I found a couple of attempts to use AV Linux natively a bit frustrating.  I really appreciate all the work (and willingness to share) by Glen MacArthur, but even simple things like trying to get blue tooth to pair with my mouse and keyboard seem significantly more difficult in AV Linux than in the base MX Linux.  Maybe it's just me...

My biggest concern prior to fully migrating from Microslop Windows 10 to a Linux host was whether I would be able to get my old RME Audio Multiface II to work in Linux, since RME Audio does not officially support Linux.  Thankfully, I found a post in this Linux RME Forum from 2020 providing valuable information.  (As somewhat expected, running Linux VMs under a Windows host is very different than running a Linux host, from an audio perspective.)

I "do" have audio working somewhat... i.e., I can play audio in a Linux browser through my Multiface, I can record and play audio in Audacity... I have not yet installed Reaper (that I used in Windows), Ardour or other audio applications.

My BEGINNER QUESTIONS/ISSUES:
Although my audio 'works' now, in Audacity, for example, I must select HOST = JACK, RECORDING Device = pipewire, PLAYBACK Device = system.
Each time I reboot the pc, I must manually restart the JACK server using the command jack_control start, even if I already started JACK using Cadence.

(1) Is it normal that I cannot select the same Device for recording and playback?

(2) Apparently starting JACK in Cadence is NOT the same as starting jack_control via CLI?

(3) How to auto startup JACK each time I power up Linux?

(4) Long-term... would I be better to eliminate JACK and fully use Pipewire and Wire Plumber?

(5) The Linux version of HDSPMixer (Hammerfall DSP) is not as 'full featured' as the Windows version.  In Windows, I could select an output mix and set channel 'sends' to that output mix, but in this Linux version, this doesn't seem to work.  Am I missing something?

(6) Should I stop fighting this battle, trying to get my Multiface II (Firewire) to work in Linux and just buy a new USB Class Compliant interace?

Thanks in advance for any guidance.