I usually use FXAA on 1440p.
Doesn't hit performance at all and still makes it look a bit better.
You can also use NVIDIA's MFAA - https://i.imgur.com/IzF1clF.png It's about 5% to 10% performance loss.. Looks just a little bit better than FXAA.

However, Anti-aliasing for 4k is definitely not needed.