In case you're running out of time, the shortest way to enjoy Neon Genesis Evangelion without losing the true essence of the animated series is:
-Neon Genesis Evangelion (the original series): episodes 1-20.
-Neon Genesis Evangelion (director's cut): episodes 21'-24'.
-The End of Evangelion.
-Evangelion 'rebuild' movies. As final stage enjoy the cinematic release of Neon Genesis Evangelion rebuilds:
-Evangelion 1.0: You Are (Not) Alone (September 2007)
-Evangelion 2.0: You Can (Not) Advance (June 2009)
-Evangelion 3.0: You Can (Not) Redo (November 2012)
-Evangelion 3.0 + 1.0: Thrice Upon a Time (March 2021)