So I don't know if this is actually a thing or what, but it seems like when I watch content on streaming (YouTube, Netflix, Prime Video), it lowers the resolution, and my display is Full HD (1920x1080), but it looks like almost 720p, even when I set the video to max resolution. I need to know if this is actually something that could happen with using Zorin, or maybe Ubuntu based OS's. I searched about this but found nothing about it, so that's why I doubt
Having gleaned from searches about Amazon Prime, they only provide SD content for Linux, HD content for Windows and MacOS only. When I used Zorin never had an issue with Netflix, Vimeo or Veoh. Are you using proprietary drivers or Nouveau, the latter giving me best results for nVidia graphics.
I can't find any extension to force this.
Have you tried Edge for linux? I don't have prime at the moment so I can't test.