This is a "science" forum, so I'm going to show you the specs and not some imaginary magic bitrate.
Nobody knows what the original upload audio format is, but the highest quality audio for this video is 129kbps aac and 136kbps opus. Pasted below is the output from yt-dlp -F, which shows all the audio and video formats available for this video. To learn which format is being played for you, right click on the video, select "Stats for Nerds", and look at the Codec line. Mine says opus (251), which is 136kbps opus as per below.
Good, enjoyable audio recording can be achieved at pretty low bitrates. Audio encoding is a solved problem. Enjoy the music!
~ $ yt-dlp -F https://www.youtube.com/watch\?v\=bJkoVhn2_hw
[youtube] bJkoVhn2_hw: Downloading webpage
[youtube] bJkoVhn2_hw: Downloading android player API JSON
[info] Available formats for bJkoVhn2_hw:
ID EXT RESOLUTION FPS CH │ FILESIZE TBR PROTO │ VCODEC VBR ACODEC ABR ASR MORE INFO
──────────────────────────────────────────────────────────────────────────────────────────────────────────────
sb2 mhtml 48x27 0 │ mhtml │ images storyboard
sb1 mhtml 80x45 0 │ mhtml │ images storyboard
sb0 mhtml 160x90 0 │ mhtml │ images storyboard
139 m4a audio only 2 │ 2.24MiB 49k https │ audio only mp4a.40.5 49k 22k low, m4a_dash
249 webm audio only 2 │ 2.44MiB 53k https │ audio only opus 53k 48k low, webm_dash
250 webm audio only 2 │ 3.20MiB 70k https │ audio only opus 70k 48k low, webm_dash
140 m4a audio only 2 │ 5.94MiB 129k https │ audio only mp4a.40.2 129k 44k medium, m4a_dash
251 webm audio only 2 │ 6.24MiB 136k https │ audio only opus 136k 48k medium, webm_dash
17 3gp 176x144 6 1 │ 3.63MiB 79k https │ mp4v.20.3 79k mp4a.40.2 0k 22k 144p
160 mp4 256x144 25 │ 3.24MiB 71k https │ avc1.4d400c 71k video only 144p, mp4_dash
278 webm 256x144 25 │ 4.09MiB 89k https │ vp9 89k video only 144p, webm_dash
133 mp4 426x240 25 │ 7.21MiB 157k https │ avc1.4d4015 157k video only 240p, mp4_dash
242 webm 426x240 25 │ 5.70MiB 124k https │ vp9 124k video only 240p, webm_dash
134 mp4 640x360 25 │ 11.04MiB 241k https │ avc1.4d401e 241k video only 360p, mp4_dash
18 mp4 640x360 25 2 │ ~ 17.38MiB 370k https │ avc1.42001E 370k mp4a.40.2 0k 44k 360p
243 webm 640x360 25 │ 10.46MiB 228k https │ vp9 228k video only 360p, webm_dash
135 mp4 854x480 25 │ 23.27MiB 508k https │ avc1.4d401e 508k video only 480p, mp4_dash
244 webm 854x480 25 │ 17.47MiB 381k https │ vp9 381k video only 480p, webm_dash
22 mp4 1280x720 25 2 │ ~ 57.94MiB 1233k https │ avc1.64001F 1233k mp4a.40.2 0k 44k 720p
136 mp4 1280x720 25 │ 50.60MiB 1104k https │ avc1.4d401f 1104k video only 720p, mp4_dash
247 webm 1280x720 25 │ 38.41MiB 838k https │ vp9 838k video only 720p, webm_dash
137 mp4 1920x1080 25 │ 133.75MiB 2918k https │ avc1.640028 2918k video only 1080p, mp4_dash
248 webm 1920x1080 25 │ 88.16MiB 1924k https │ vp9 1924k video only 1080p, webm_dash