If you're an academic and are not using the Sioyek PDF reader to read papers ... you should try it. It has the ability to jump to references (or other sections, or figures, etc.) and back - or display them as an overlay right where you are. Even if there are no explicit links in the PDF! Easily look up stuff on Google Scholar (or other search engines.)
It's a bit idiosyncratic and does have somewhat of a learning curve, but if you spend a lot of time reading papers, it's worth it.
Nice video tutorial covering major features: