Unhook[1] has been my go-to for this. Gives full customization over shorts, recommendations, comments, etc.
1a: https://addons.mozilla.org/en-US/firefox/addon/youtube-recom...
1b: https://chromewebstore.google.com/detail/unhook-remove-youtu...
Does it still work for you? Unhook hasn't been updated in years and doesn't work for shorts anymore, on Firefox. It's still worth it to get rid of the suggested videos though.
Some of the Unhook options are broken nowadays I think. Its that or one of my other 10 YouTube extensions I now have to deshittify that damn page. Disable translate, SponsorBlock, Disable AutoPlay, some better thumbnail thing..
I clicked comments to say the same thing. Can recommend
Sadly, it hasn't been updated since 2024 and is slowly breaking. Haven't found a good replacement yet.