DLSS 2.0 can reconstruct 1440p even from only 576p quite well
https://imgsli.com/MTUwMDg/1/2
Compare the 576p DLSS mode to 1440p quality
You can see here 576p DLSS 2.0 compared to native 1440p and it does look a touch softer but not a big difference. According to the guy who posted these images in motion while playing the game he couldn't even tell see a difference.
Who knows DLSS 3.0 likely will be even better than this.