i bookmark a lot of channels as well. for my most watched channels i also add them to newsblur since it makes it easier to see when new videos are available without having to go to each individual channel. there are a few other rss readers around that support adding youtube videos as well i think

ublock origin is another tool that comes in handy for blocking things like the sidebar suggestions. just add this to the 'my filters' page:

www.youtube.com##ytd-item-section-renderer.ytd-watch-next-secondary-results-renderer.style-scope