Don't waste willpower on this.
I've lost years of my life to YouTube. I recommend finding somebody that you trust and having them set a parental-control password on your devices.
I use apple devices so it's pretty straightforward. My wife set up a 20-minute screen time limit on YouTube.com in safari, as well as Chrome and Firefox and the YouTube app.
My only current workaround is to use mpv/youtube-dl, which is fine in a pinch. It's enough friction to keep me out of the YouTube pits!