Since my teenage years, I've used a lot of youtube and noticed that it took a lot of time of my days. Only recently have I been having a much healthier relationship to it. This is how I reduced around 80% of my youtube usage.
Turned off google history
Most of the time, I did not feel like I was in control of my youtube usage. This was due to endless scrolling of recommendations and suggestions of next videos to play, which captured a lot of my attention. Turning off google history on my google profile settings disabled the Youtube's homepage feed and some search suggestions. As a bonus, it reduced the amount of data that Google harvested from me :).
Installed a browser extension
I installed UnTrap for Youtube. It allowed me to remove many website features and possible distractions.
Removing the Shorts feature was a big one for me.
Decluttered my subscriptions
I removed around 95% of my subscribed channels. This was very critical to reducing the usage. I removed all the cheap entertainment and bad quality channels that had been laying around for years, and the feed quality improved a lot. Now I only keep around 5-10 subscriptions at a time, which are mostly news channels and other interesting hobby and work related ones.
Deleted phone app
I opened the mobile app for no reason all the time. I just opened it to see if there was anything new, and for no other good reason. I figured this was a slot machine dynamic in my life that I wanted removed, so I'm trying to not have youtube on my phone. I can still use the phone browser to watch videos if I want, but it will be more mindful and less distracting.