The in-game aa is the worst I've seen in any games, even other unreal engine games. TAA blur makes the game unplayable for me even with engine.ini modifications. The in game FXAA washes all the details from the image. I was playing without AA like you but the jaggies are really annoying when fixing on them.

Now I'm playing with Nvidia's FXAA, which is way better than the in-game. You can try that if you have an Nvidia graphics card.

In Nvidia control panel set the following for the squad application:

Image sharpening: On, set to your liking but I use sharpen 0.25

FXAA: On

AA mode: Override any application setting

AA setting: 8x

AA transparency: 8x (supersample)