Bluetooth audio noise cancellation?

Bluetooth audio noise cancellation (Grounding problem?)

Hello, I need some beginner advice on audio circuit filtering and grounding.

I'm building retrofit car Bluetooth support and I have major audio quality problems(rattling,crackling). Most likely due to grounding/DAC.
I'm able to get good audio when I poke the wires multiple times. If I touch them again, it starts crackling until I find the good spot again.

I'm using BLK-MD-SPK-F module. I used SPK-E before, without having such audio problems.
Here's the schematics:
https://img.auctiva.com/imgdata/1/6/8/7/2/3/9/webimg/659594556_o.jpg
I'm not using the OP-AMP, just driving the sound signal directly to the stereo input. Is this a problem? I doubt it, because I can get good quality audio just by fiddling wires around.
I have connected DAC input directly to 3.3V. Is this correct?(When DAC was floating, the audio quality was horrible, barely recognizable) I don't know the function of the DAC in this circuit.

Here's schematic of the DAC configuration:
https://img.auctiva.com/imgdata/1/6/8/7/2/3/9/webimg/659594563_o.jpg
Do I really need another regulator for the DAC?

I think there is 2 types of ground in the module; DAC and RF. How am I supposed to connect these correctly?
I have e.g. stereo external case GND and also internal regulator GND available.

I have randomly tried different ground options/filtering caps/resistors without much luck. I have no experience in audio circuits.
The audio input configuration itself is not the problem, because if I directly feed 3.5mm AUX to the stereo, the quality is perfect. The input is going through 2.2uF capacitors for each channel. The problem is in the bluetooth module grounding.

I'm not audio fanatic, so I'm okay with any sound without major noise. I need a reliable solution here, that is based on knowledge rather my trial&error solution.

Thanks for reading and I hope to hear some audio tips from the experienced guys!