Last time I looked (admittedly, years ago), most resources seemed to be in the vein of "here's Fortran 1990, and once you've learned that here are a few chapters on F03 and F08, treated separately".
It'd be great to learn there exists a "Fortran: the good parts" sort of thing that just completely elides the outdated stuff.
Also https://fortran-lang.org/en/ is a good hub to find more information, packages, etc.
https://fortran-lang.org/en/learn/
BTW, the Fortran Lang website (https://fortran-lang.org/) is THE official website of modern Fortran, maintained by the modern Fortran community.
You may also take a look at the modern Fortran discourse at
https://fortran-lang.discourse.group/
where you can find all the gurus of modern Fortran. They are very willing to help if you post a question. I have asked all my Fortran questions over there during the development of PRIMA.
Modern Fortran is quite different from Fortran 77, while being as powerful, if not more.
In addition, there has been a significant community effort on improving and modernising the legacy packages, the ecosystem, and the language itself.
With projects like LFortran (https://lfortran.org/), fpm (https://github.com/fortran-lang/fpm), and stdlib (https://github.com/fortran-lang/stdlib), I believe that Fortran will enjoy prosperity again.