I cropped to a 4:5 for both instagram and facebook and then instagram i did 1080px and facebook I did 2048px. After I sharpened them, before posting I zoomed in and it looked great to me. Then when zooming in a little on social media, it looks not as sharp. Not blurry, just not like it should? Which I'm totally guessing, but thinking I sharpened too much making it look like that. I have posted soft or noisy photos (prior to taking your classes of course) and the quality didn't drastically change once uploaded. Which is why I don't think this is social media just degrading the quality, I am clearly just doing something wrong.