This week, I ordered an FP4 3 times. All devices had a sound problem during calls; noisy, tinny and choppy sound. Both on my side and that of the receiver. And both to mobile and landline numbers.
I read earlier posts about this.
I tried the following things:
Wifi Calling off
Permission Google for microphone off
Network 2G/3G
Network free choice
Is there anything else I can do to improve the sound?
When I play music through speakers there is no problem. When I connect a headphone with a miniusc-jack I hear noise.
Among the posts you’ve read, did you see this one? I mention it because, while you withdrew the Google app mic permission you don’t say that you deactivated the app itself.
Regarding audio playback through a USB-C DAC adapter, unfortunately results vary considerably. There’s a topic with more info here.