I'm new here. My apologies if this is an inappropriate posting style etc.

Well done!
I got my Teensy 4.1 and audio shield maybe 2 hours ago. After soldering it on, I have already tried the "Examples->Audio->Synthesis->Guitar" sketch, to great amazement and pleasure, and then proceeded, as I don't read manuals being a typical human and such, directly to patch a "USB-In" object to an "I2S-Out" object, add the I2C control for the whatever5000, export, copy-paste, and after about 10 minutes wondering why no sound, figured out (thanks to the forum),
that one needs a buffer AudioMemory(number); in addition to whatever5000.enable(); and whatever5000.volume(0.5);

now I have an ALSA audio interface playing wav files.

This is more progress than I had in 6 months of trying to fiddle with the tooling for the Archmix, nor would I ever have imagined being able to bring up an I2S and I2C interface and audio codec so quickly, let alone having the luxury of so many USB modes including a default class-compliant USB audio driver! egads. this is great.
I can finally get on with getting on.

Thank you all so very much, I may just finally end up being productive after all