I like Open Camera. Also let’s me select audio source, and there’s “unprocessed option”. Usually needs tune up with audacity to increase volume, but my phone’s audio processing sounds like 8kbps MP3.

Here’s a sample, same recording conditions.
Default: https://files.catbox.moe/d2n7sg.flac
Unprocessed: https://files.catbox.moe/xf9ab8.flac