Tongues by Clancy Nacht

Cosmically tormented FBI linguist Ekon is the only one B-list heartthrob Chris will talk to about the Farm, a horrifying cult of which he’s the only known survivor. As they bond over mysterious pasts and their unsettling attraction, Ekon discovers an eldritch power his government bosses would love to exploit, one that could spell the end of everything.
While there are queer and romantic elements, this is a horror novel.