1) I'll tell you a secret - in the application, the scale is set to 200% (as opposed to the pre-retina), because at this scale the image looks like it will look on the website (the actual size if you attach the ruler to the screen). And it is at a scale of 200% that your application for some reason begins to render the text clearer/sharper (unlike Photoshop) than it actually is and will be in final png image
2) For some reason, you ignore the problem indicated in paragraph 2.
I have all the standard settings, both in Affinity and in Photoshop.
All your answers sound like I'm an idiot. And this is support for a paid product. Thank you, I made the appropriate conclusions.