2.7k Video Pixelated After Export

Hello, 

I'm fairly new to Premier Pro and have been struggling with  poor quality exports. The export is always pixilated and generally much lower quality than my original footage. 

I shot in 2.7k on my GoPro at 60fps. I have tried as many different export settings as I can find only (match high bitrate, youtube 1080p/4k presets) but always has the same results. 

I created the sequence from the source footage. I have attached screenshots of the relavant settings.

It would highly appreciate it if someone could help, I'm guessing it might just be a simple mistake somewhere! 

Thanks in advance 🙂 

(btw this video is for youtube)