I think they fit in similar categories because many mecha animes deal with themes of exponential escalation, which I suspect was heavily influenced by the collective national experience of a total war that culminated in daily firebombings of cities, and ultimately (being on the receiving end of) the only wartime use of nuclear weapons in history.

However, both series deal with that escalation in different ways. While in TTGL, the escalation is purely physical - the villains get perpetually stronger and the heroes have to strengthen themselves to stand up to them - the escalation in NGE is more personal.

“Why do you pilot the Eva?”, Shinji asks Rei and Asuka, a question with an answer seemingly so obvious that nobody else in the entire series asks it. And yet it gets to the heart of Shinji’s development.

In the beginning, he’s a terrified teenager who is in way over his head. As time goes on, he becomes more confident in his ability to pilot the Eva, yet his experiences leave him a shattered husk of a human being.

I think (and this somewhat gets into spoiler territory for anyone that hasn’t seen NGE yet) that the answer to the question of what happens when someone is put through so much trauma that it destroys who they are is that there is nothing in a void. Community can help repair the damage but some things can’t simply be handled by the self, no matter how hard one tries, how dearly they want it, or how capable they are at other things. At least, that’s the impression I got from the ending.