Device: Ulefone Armor 24 (cheap-ish Chinese brand)

The default audio quality is absolutely awful. It's like this everywhere, including the default camera app.
The issue shows up with external microphone as well.

Basically it sounds like over-compressed audio that gets easily beaten with 22.5kHz 64kbps MP3 (comparing to what I listened to recently).

I've found this audio recorder app that allows selecting audio source manually, including "unprocessed" audio: https://gitlab.com/axet/android-audio-recorder
The result is far better.

Audio recording samples

I just recorded music playing from my laptop, so yeah, the audio source isn't that great either, but you can hear the artifacts there.
Both were recorded lossless.

Default

https://files.catbox.moe/e33ufc.wav [2.7MiB]

https://files.catbox.moe/d2n7sg.flac [1.4MiB] - converted to FLAC for in-browser playback

Unprocessed

https://files.catbox.moe/xf9ab8.flac [2MiB]

Basically, it's just missing some noise-cancelling, but other than that, it's far better.

I don't care if disabling that potentially screws up phone calls, I don't like those anyway.