Anyone want to rant about their favourite anime with me? :D

I love code geass because It's completely opposite of AoT, in term of the hidden message If attack on titan believes focusing humanity's attention and hate into a single enemy won't work for long and makes it easier to corrupt the social structure of the world. But Code Geass thinks it's perfectly fine to do so, with that utopic ending. Lalouch the anti-Hero also exploit the idea of becoming evil to defeat the greater evil. He's basically like a more successful Light Yagami

Yeah, Code geass is massively more optimistic about human nature than AOT, which is definitely part of why I love it ( apart from Lelouch just being awesome) That said, there is quite a lot of difference between the situations which do make sense as reasons for why one doesn't work and one does. Lelouch does have the entire UFN, Nunnaly and the black knights to work together after his death make sure the hatred is directed in a helpful direction (and who critically aren't corrupt and can proven populist using the hatred to rise to power), whereas in AoT if I remember correctly the entire political structure is corrupt and people have got used to living in awful conditions--meaning there's unlikely to be popular uprisings against any corrupt governments, and that any leaders are more likely to accept the state of affairs and just focus on their own benefits rather than working to better humanity. Of course, the difference in the Worlds is part of the way AoT represents a bleaker outlook on humanity.

I think one of the most underrated anime ist Psycho pass. A perfect representation of a society , which have traded its freewill for security to an AI overlord

Psycho pass is a bit... Out there (in a totally fabulous way, of course) in how it portrays a future under AI rule, but it definitely does have a point to make about blind trust of authority and the necessisty of evil which is really interesting. It is 100% underrated.

Thoughts on Phantom requiem for the phantom? I feel like it gets slept on too much with how good it was....

Welcome to MO. I hope you have fun here and make plenty of friends. :) My top anime are probably FMA:Brotherhood, G.T.O., and Monster. All great shows for very different reasons for me.