Bit perfect Apple Lossless to DAC

Hi all,
I've revived my 2014 Mac Mini with Ubuntu and it runs really well. I have both Spotify steaming music and my 500 CDs ripped to the SSD as Apple Lossless audio files.

I use the optical out headphone jack, Toslink, to my external headphone DAC and headphones (Chord and Sennheiser).

Playback worked but not for the Apple Lossless files.

However, the output is not bit perfect as the software is allowed to volume control, either in Spotify or the system tray. My DAC has its own volume control so it needs bit perfect output to get faithful audiophile quality. I can tell with classical music that the software is degrading the quality.

So, unfortunately I started Googling and messing with stuff to overcome the inability to decode Apple Lossless (gstreamer missing plugin) and for using ALSA not PulseAudio.

I have installed various things via terminal and now have no sound from Spotify or my media player, guayadeque.

How do I fix these two issues?

1) install codecs for Apple Lossless

2) get bit perfect sound to the optical out for my external DAC

Thanks!