End of Evangelion (optional, but recommended. This happens chronologically at the same time as Ep 25 and 26)
Everything else (optional, not recommended)
The OG series is the story Anno wanted to show. Some fans wanted a more concrete ending, so Anno gave them a concrete ending in EoE. Then some fans wanted a happy ending where Shinji gets the girl so Anno said fuck it, sold out, and made a series with a happy ending where Shinji gets a girl. But now some fans want a happy ending where Shinji gets the right girl so Anno gave up on them as lost causes and went and directed Shin Godzilla.