The King in Yellow by Robert Chambers is not modern, but it is what inspired Lovecraft, and Chambers is a far better writer. It’s several short stories, is pretty accessible, and has some moderate critiques or observations on society that are still relevant.
Important caveats - it’s not all horror. Chambers was mostly a romance author who occasionally did horror and it shows near the end of the collection.
The beginning of the first story is pretty jarring to modern sensibilities, but Chambers was probably not a racist, and it was probably meant to be jarring even for readers of the day. It’s a story where you have to remember the author is not the narrator.
Michael Shea’s mythos stuff is pretty good I think. ‘Demiurge’ is a book collecting all his stories. He updates them to the then contemporary 1980s, keeping the elements of cosmic horror but putting them in more modern and relatable situations rather than attempting to make them period pieces.
