It'll keep continuing until you get one FPS and no audio without paying for premium.
Downloading with yt-dlp results in full bitrate if the "AV1" format is selected. Well, last I tried.
MPV has a yt-dlp plugin (historically still referenced "ytdl") if you want to watch once and burn the download: mpv -- ytdl://video_id_here. Note that if the video is 4K or 8K, it will play that and not auto switch.