2020 Toyota Tacoma and Rockford Fosgate DSR1 / iDataLink: volume inoperable with CarPlay

The Rockford Fosgate DSR1 Digital Signal Processor with iDataLink is an excellent solution on paper for integration of stock factory automotive stereos that retain stock operation. (Including factory head unit operation, and steering wheel controls.) The DSR1 allows per-channel levelling, time delay, and band, high, and low pass filtration. The DSP allows for 8 discreet channels out at line level, after the automotive CAMBUS data is decoded on the Rockford Fosgate side, and routed via cables and decoding by the iDataLink Maestro side of things.
In this particular implementation, I've found that the system works as described for Apple iPhone, but not for Android. (S22 Ultra, and S8.) When using Android, the volume cannot be changed via the head unit or steering wheel, and appears to retain the exact (numeric) sound level that was last used successfully through Bluetooth- where the audio (music especially, as Navigation and Text Message reading have their own random levels in this mode,) works perfectly, with expected fidelity, and can be controlled as designed in the mobile Rockford Fosgate Perfect Tune app.
I am currently engaged with iDataLink regarding this technical hiccup. An important step in troubleshooting for them is a video where they can see what happens with the issue being described- so this is that video.
In the video you will see my S22U playing a Pink Floyd song, so I will edit the posting to avoid copyright ghosting shortly after upload. Trust me when I say that the audio was fine using BT. You will see me adjust the radio knob and the steering wheel control. When done with this step, I set the volume to "14" and removed the USB cable from the charging (cigarette charger) port and insert into the Toyota CarPlay USB port. At this point, music resumes, but the volume cannot be changed via the radio or steering wheel.
Hopefully, iDataLink can solve what appears to be a fairly insignificant (for them) technical issue, and I can use my system like I did previously in a stock configuration- through the CarPlay port. Normally, I would let this go, but I CONSTANTLY use navigation and frequently must interface with text messages via voice, so this mode is very important for my needs.