Mazda 6 2020 Bose system dsp upgrade issue

I just gotten a used Mazda 6 2020 Bose system.

Would like to know what is a great way to upgrade my existing system. Default bose sound muddy. However I have added a helix v12 dsp. The sound stage is way clearer and wider now yet when it appeared to have a worse SQ. it sounds worse than a default bose setup.
The dsp was connected via a harness to the bose amp. No speaker was changed. Just added a helix dsp. tuned via wired carplay connection to my spotify.
signal was tap before amp according to the installer.

However, he mentioned it is challenging to do DSP for this car due to factory bose amp. Resulting in massive drop in Sound quality.
I switch the input to the bluetooth on the helix. It sounds amazing. was thinking if there is anyway to fix this? Or is it a common thing?
 
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