I have 459 titles on my IMDB watchlist and a tiny percentage of it is available on Netflix (if at all), but this is anecdotal and might have to do something to where I live.

Netflix outside of the US is a very different experience.

In the US, it's mostly their own productions and older content they explicitly acquired, but elsewhere, especially in markets that don't have a local HBO or Disney streaming service, they have incredible backlogs.

I remember finding basically everything I could wish for on there when traveling in SE Asia almost a decade ago, compared to a still decent offering in Western Europe, and mostly cobwebs in the US.

459!? It must take a while to check your list…