If you quit YouTube then you also quit all the content on YouTube that isn’t elsewhere. The best solution if you still want to use it is to use 3rd party apps. Personally I would actually count that as having no reliance on Google in particular anymore. If a video platform owned by Google wasn’t the most popular then it would be another platform. I don’t think you should think of 3rd party apps as YouTube frontends, but rather, apps that scrape videos hosted on Google’s servers.
“De-googled” is just a word. And it doesn’t really apply here. Like the word “banana” also doesn’t apply to what I do on my phone… The interesting question is: What is your goal? What are you trying to achieve? YouTube still sends you the data. And they log your requests. But you don’t have an App anymore that is designed by Google to track you some more and make the ad playback more smooth…