Lain is about an AI girl who convinced herself she's a real girl. It's fucking Pinocchio. It isn't deep and the message applies to no one. It meanders along and stretches it's runtime with shots filled with literal white noise because it had no budget.
Evangelion accurately depicted how abused children exist in a hyper competitive society where their worth is determined by their performance in battles that are metaphors for growing up.
It talks about neglectful parents. It also shows children that suffered PTSD and how they manage it as adults.
The battles were amazing, and they perfectly depicted the weight of giant fights as every step an Eva takes crushes pavement. The animation was still in the golden age of pre CGI and the shots hold up.
It's not even a contest. Saying you like lain and trash talking Eva is the biggest pseud take. Lain is literal white noise trying to pass off deeper themes with no execution or performance. EVA is all grand epic science fiction that explores the actual real human condition. And with 4 movies and the original tv series there's more to cover.