I am not a developer, but something like AdBlock or uBlock Origin should be able to at least highlight the "Sponsored" text to make it more prominent?
uBlock Origin appears to remove a lot of the sponsored results. Some sections like "our brands" or "expertly reviewed" may still appear above organic results.
I used the element picker, "##.acs-private-brands-container-background" seems to block the "Our brands" element.
Sponsored products can be removed by using any of the major ad-blockers. When I worked at Amazon we actually worked with the add-on authors to make this easier. Previously sponsored products were present but looked kind of broken when using ad-blockers, so we added some hooks and contributed rules to the plugins.
Probably using stylus to update stylesheets on those specific ad's classes. But, amazon changes things so frequently that someone needs to constantly always update these scripts/stylesheets
Well, the advertised content seems to have an ad___slot and an AdHolder class so I can probably whip you up something in stylish I guess whenever I get off work (posting as a reminder) .