Text in png & jpeg export is fuzzy, not sharp, but it's sharp in pdf export

I'm exporting an image with text on it (100 pt Fino Sans and 20 pt Quicksand). When I export a png or jpeg file, the text is fuzzy at 72 ppi & 96 ppi export settings. It looks better at 300 ppi export setting, but I need this file to be under 1MB; it will be attached to emails for viewing on-screen (not printing). The image looks fine at any resolution. I have anti-alias checked.

When I export a pdf, the text is sharp, but the image is pixelated. The resolution of the image is higher than the resolution of the document, so while this is not my main issue (I don't need this to be a pdf), it is perplexing.

I need this file ultimately to be a jpeg or png. The only workaround I've found is to screenshot it, but since I need to make a number of these, that's not ideal. Any ideas on what could be going wrong? Thx