Disney's market cap is about $320B, and Netflix at about $280B. It isn't unreasonable to expect that YouTube would be valued at at least that if it were valued independently (Alphabet overall is $1.9T - YouTube as 15% of that value seems reasonable).
YouTube seems to be on track to overtaking Netflix this year in terms of revenue as well, if it hasn't already. [0]
Disney holds that crown. There's no likely scenario where YouTube by itself will surpass Disney, especially given how well Disney+ has performed.
Netflix is also a lot more valuable than YouTube and far larger in terms of sales.