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.
I wouldn’t. Most YouTube alternatives that hook into YouTube for content are always going to be in the tenuous position of “It works until Google decides to drastically change things.”
I think it’d be easier to not become dependent on YouTube’s content in the first place when there is always that chance they pull the rug out from everyone.
You don’t count using YouTube scrapers as de-googling because Google might make it break some day? That makes no sense.
Why is that? It’s Google’s content you’re still consuming, ergo you have at least some measure of dependence on Google to continue accessing it.