Exports are extremely pixelated in illustrator, even though the file is set up correctly?

Wondering if anyone else has had this problem/knows a solve? 

I am exporting some screen content (1920x1080px) at 300ppi in illustrator, exporting as a JPEG (and tried PNG)at 100% quality -- and yet, the export is coming out super pixelated/not sharp. I export frequently at this size for my work and it always is high quality in exports, so I'm confused why it would not be working when I'm doing the same thing as I always do for every other project. Attached is how the file looks in illustrator (and should look) versus how it exports. 

Thanks in advance!