ID files exporting fuzzy and not at size designed

For many years I have designed things like digital ads in ID, exported as png or jpg and they have been crisp and at the size that I designed it out (example 300x250). With the latest updates I can no longer do that. The files are only sharp when I export at 300dpi but are much larger in size (around 1200xsomething).

Some of the solutions I have tried:

playing with dpi 72/96/300 - didn't result in sharp file after export at size

exporting from ID as a PDF and resizing in photoshop but is still blurry at size

exporting from ID at 300dpi and resize using websites/mailchimp etc just to see if that worked, still fuzzy

redesigned in photoshop, exported still fuzzy

redesigned in illustrated, exported to size and still fuzzy

used both mac and pc, no difference there

The only partial fix I've found is starting the design under "web" and exporting at 72dpi with "high" (exporting at max results in a fuzzy file).

I've asked several colleagues from different orgs and they are running into the same issue themselves (trying it out with their files, not mine!). Anyone else see this? Is there something you have to change in creating a document that sets it up better where it doesn't loose quality? WAs there something that use to be automatic that now we must do manually?