Seconded, but just a note that if you're using ublock origin you can just block the sidebar with a content filter.
I've blocked the sidebar and the comments section. The former has dramatically reduced the amount of time I spend on YouTube. The latter has dramatically reduced my exposure to the inanity of the YouTube comments section. Both are huge quality of life improvements.
This extension has been more effective for me than any other at cutting down how much youtube I watch. Maybe the biggest factor in this is that it doesn't ban me from youtube entirely - When I've tried extensions like that in the past, I've always ended up uninstalling the extension when I needed to watch a youtube video for work. This way, I can watch a little, but the lack of constant new recommendations keeps me from spending hours and hours on the site.