This is a script from a now deleted Reddit user. It works as of 05/26/2024. You paste it into the web console in your browser. It will delete one comment every 3 seconds due to limitations by Google.

bulk-delete-youtube-comments.txt

# https://myactivity.google.com/page?hl=en&utm_medium=web&utm_source=youtube&page=youtube_comments

c=[];
for(i in e=document.getElementsByTagName('path')){
    typeof(x = e[i])==='object'? x.getAttribute('d').includes('6.41z') ? c.push(x.parentNode.parentNode):e:e;
}
setInterval(()=>{
    c[0].click();c.splice(0, 1)
}, 3000);