Windows XP’s media players (Windows Media Player 11, VLC 2.2.8) struggle with 4K or HEVC codecs. Stick to H.264, 720p, AAC audio.
Run yt-dlp on a , but serve as a HTTP proxy that XP can use: yt-dlp windows xp
If yt-dlp is too difficult to configure, several alternatives still function on XP: Windows XP’s media players (Windows Media Player 11, VLC 2