I have a ublock rule like:

    www.youtube.com##div.ytd-rich-item-renderer:has(ytd-channel-name a[href="/c/SOME_CHANNEL_HERE"])

Huh? On the front page I can for each recommended video select "Not interested" or "Don't recommend channel". This is on Firefox both desktop and Android.

Is it different for you?

Blocktube and sponsor block browser extension.

On creator focused networks like YouTube, tiktok or instagram your recommendations get reset if you accidentally open a link to a video or channel you marked as “Don’t recommend this X.”.

If you really want to nuke them from your feed the easiest way is to report them. Might be ethical questionable but the 99,9X% of reports get ignored anyway so why not use it as feature.