I found a brand new copy of The End of Evangelion in eBay. Do I have everything now and should I watch them all 45 times to understand everything?

If this is the continuation from this post, then yes.

I would personally say that you should definitely pay more attention to the original than the Rebuilds. It’s not that the Rebuilds are something that don’t deserve that, it’s because the movies (which are a different take of the series) aren’t nearly as philosophically heavy as the original series + 1997 movie. They do require multiple showings though, so keep that in mind. There are a few things that you should still pay attention to regardless of not as much deep, philosophical commentary, such as the existence of the 4 Adams in the Rebuilds, Mari’s backstory, among other things I most likely have missed.