max_res setting doesnt affect audio quality

[Emppu45]

Hello.

In Yewtube command 'set max_res 2160' doesn't seem to affect audio quality.
I have set 'max_res 2160', 'show_video false' and 'player mpv'.

I have tried checking the max audio quality of a youtube video by running
$ yt-dlp -F 'https://www.youtube.com/watch?v=LDU_Txk06tM'

with the output:
[youtube] Extracting URL: https://www.youtube.com/watch?v=LDU_Txk06tM
[youtube] LDU_Txk06tM: Downloading webpage
[youtube] LDU_Txk06tM: Downloading android player API JSON
[info] Available formats for LDU_Txk06tM:
ID EXT RESOLUTION FPS CH │ FILESIZE TBR PROTO │ VCODEC VBR ACODEC ABR ASR MORE INFO
────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
sb2 mhtml 48x27 1 │ mhtml │ images storyboard
sb1 mhtml 80x45 1 │ mhtml │ images storyboard
sb0 mhtml 160x90 1 │ mhtml │ images storyboard
599 m4a audio only 2 │ 723.52KiB 31k dash │ audio only mp4a.40.5 31k 22k ultralow, m4a_dash
600 webm audio only 2 │ 814.59KiB 35k dash │ audio only opus 35k 48k ultralow, webm_dash
139 m4a audio only 2 │ 1.12MiB 49k dash │ audio only mp4a.40.5 49k 22k low, m4a_dash
249 webm audio only 2 │ 1.17MiB 51k dash │ audio only opus 51k 48k low, webm_dash
250 webm audio only 2 │ 1.54MiB 67k dash │ audio only opus 67k 48k low, webm_dash
140 m4a audio only 2 │ 2.97MiB 130k dash │ audio only mp4a.40.2 130k 44k medium, m4a_dash
251 webm audio only 2 │ 3.10MiB 135k dash │ audio only opus 135k 48k medium, webm_dash

The highest available audio should be number 251 with the file size of 3.10MiB. However when playing video in Yewtube, reported file size is "0Mb".

System info:
OS: Artix Linux x86_64
kernel: 6.2.2-artix1-1
Shell: zsh 5.9
Terminal: kitty
yewtube 2.9.4