Exporting and Sharing to Social Media at horrible quality/ low resolution

Using the web app on EDGE, paid subscription (if it matters). Both downloading a file as PNG/ JPG produce blurry images, and sharing directly from express to LinkedIn & Facebook result in blotchy and blurry images. See the attached Screenshot comparing express to Facebook: the words, image and lines are blurry, and the colors are mottled. Especially in the Logo. 

My attempted fix was to download the image and upload directly on the social site. When downloading the PNG the library image in the file came out horribly blurry, but everything else was crisp. JPG came out crisp, but still turned out horribly blurry when posted on social media. 

I've seen a lot of complaints on here of blurry images and media, but no solid resolution how to fix it or specify export quality.