This is probably best possible quality one can achieve on youtube.Each song is about 50GB file size encoded in Prores HQ and upscaled to 8K.Unlike 4K resolution 8K resolution forces youtube to use better and new AV1 codec.Just be sure to change it in youtube settings AV1 always on:    / account_playback  
Also you can wath in 8K on 1080P display.Its really not about resolution.Think of it like quality and bitrate settings in streaming service:
8K-max bitrate and quality
4K-high bitrate and quality
1440P-medium bitrate and quality
1080P-low bitrate and quality

KamiBand - Hideki Aoyama (Drums), BOH (Bass), Takayoshi Ohmura (Guitar), Leda Cygnus (Guitar)