2PC 1440 to 1080 Settings

[Dvk1211]

I have a few questions, my streams a bit blurry when I watch it live via my phone or another pc. I have a 2pc setup with a NZXT 4K30, I play on 1440p 144hz my stream pc has 2 1080 monitors. I want to stream in 1080, do I set my base canvas to 1920x1080 or the 2560x1440? Then output to 1920x1080 I would assume? Looking for the best solution to make this as clear as possible. Thanks!!