Despite the title, I don't think YouTube is the main issue... You can replace it with tiktok, twitter, your favorite video game, watching TV... and that still sounds unproductive and unhealthy. In fact, I'd rate short videos and fragmented social media content worse digital distractions than YouTube.

To help me disconnect, I set my phone to turn on power saving, grayscale, dark mode, and max redshift after 11 PM. It makes it so annoying to use that I can just put it down.

Don't worry too much about being unproductive outside working hours. Worry about unhealthy habits that will eventually harm your productivity.