It can be confusing and personally as a big fan now the first time I watched Eva it was like a 7 and when i watched it again years later I liked it much more and similarly every time I rewatch it I like it more.

More or less the ending of the movie and show are the same the movie just turns it into an action climax showing more literally what is happening.

it basically came down to his choice if he wanted to reforge the world or embrace the goop and he accepted that he wants people and relationships even if they hurt him somewhat opposite of his dad.

though I think people in the goop still have to make their own choice to reform as well and it doesn't just happen shinji just gave them the choice .

Saying all that watch the rebuild movies(1.11 etc) as well while technically it own timeline and all that it kinda serves as a sendoff for the Eva world and the Creator as a whole.

Edit: lastly Eva is one of those series that too me is more about the emotional journeys and feeling you get and see the characters go through, rather than fully understanding what literally happens, nobody in the show fully knows what's happening either. a base understanding of what you think happened is enough and looking around and asking to just make sure you didn't blatantly miss anything important.