hi mate
Does the ntr section of this game have a lot of content?
Not really. It's all optional. Evelyn uses every weapon at her disposal to leverage negotiations with Thaddeus. Nothing happens until the MC tries to talk to Thaddeus when E and T's portraits are next to each other at City Hall. The first time the MC does that, he sees them kissing. You have a choice to interrupt and tell Thaddeus to buzz off, or to watch but not interrupt. Interrupting causes the entire thing to end. You lose a small weekly supply of money from Evelyn, and she likes you better, but there are no other consequences (you can still talk to thaddeus when he's not busy for hints about quests or to train up your courage even after telling him to stop).
You don't need a lot of money in the game, so there's no real downside to interrupting them ASAP if that's what you wish. It's somewhat harder to finish Evelyn's romance path if you don't interrupt them.
There are three scenes of Evelyn and Thaddues together: kissing, oral sex, and anal sex. If you continue to look in on them but avoid interrupting, you see all three in that order, then the scenes repeat. Seeing all three scenes unlocks one of Evelyn's gallery entries. Each time you see a scene, the amount of weekly money from Evelyn increases (the idea being that the money is a gauge of Thaddeus's happiness). And that's all there is to the NTR content.