DSP? Could this be sound shaping? Is it possible that they measured the in-car audio, set a flat in-car response, and then provided better user controlled eq settings on top of it? One can only hope, even though I have got our sound to where I find it to be quite good.
Before you try this update some superstition based on my own experience with MID for the 2020. Have your phone's Bluetooth off so that the phone isn't playing with the head unit while it updates. Don't rely on an external charger but instead run the engine during the whole update. Don't open the passenger door during the update - I had the passenger door open when my first attempt failed - probably coincidence. Some people have had success just running off the car's battery (no external charger, engine not on) however if your battery is weak it could cause a problem. Someone measured 10 amp draw on the car in this "on" mode without the engine running, and the process could take up to an hour for some folks (especially MID files).
As a reminder, all extracted files should be root in an NTFS (or Mac OS Extended per forum members) formatted USB stick, not inside a folder. Many extractions automatically create a folder and put the files in there. The files must be at the root of the USB not in a folder. Don't have any additional files or folders on the drive. Anecdotally people are saying the right USB slot works more reliably than the left.
After the process is complete, you shut off the car, open and close the driver's door, the car may need additional engine-on runtime (maybe up to an hour) to do some sort of internal initialization to truly complete the installation before the system will be at its best. This doesn't require any special procedure, but just so that your expectations are tempered. It may take several short trips or one long trip before the system fully does whatever it's doing internally.
Attached at the bottom of the post are the installation instructions: 15-261-20R_121720.pdf
15-261-20R Technical Service Bulletin Reprogramming File Availability for Optimization of Gen 4 Denso CP1 Infotainment Systems Dec 18, 2020 courtesy of @chvvkumar