Vocal Remover Isolation Not Perfect

a repost this time. When i download musics from youtube using youtube-dl and isolate vocal is not perfect. I still hear 99% of instrumental but the vocals is loud volume. I followed this Tutorial - Vocal Removal and Isolation - Audacity Manual and i noise reducted it. Nope it doesn’t work. even i did the bass to center it didn’t work again. It Commonly lowers down the volume. Vocal remove is almost perfect. I cannot use AI Websites because they are not free. and i need a open souce/free of vocal remover and isolation. Can anyone know why this happened? and the downloaded music from youtube dl is mp3/

Try the new AI Plugin tools OpenVino:

Peter