Steamy excerpts are a genuine reader dilemma: you want a genuine sample of the author's prose style and heat level before committing, but you don't want something just crudely ripped from context. I've had good luck with the 'Look Inside' feature on major retailers, as it's the actual text. Searching the author's name plus 'excerpt' often leads to their official website or blog where they post a chapter as promotion. That's the most tasteful route—it's curated by the creator, respects copyright, and usually includes a link to buy the full book. I'm wary of random aggregator sites; the formatting is often broken, and you never know if the upload was authorized.
BookTok and dedicated romance review blogs are another angle. Reviewers will sometimes quote a particularly memorable line or paragraph in their critique to illustrate the book's vibe. It's not a long excerpt, but it's a solid, in-context taste. My personal rule is if I can't find an official snippet after ten minutes, I just check the book out from the library app. Skimming the first chapter there usually tells me everything I need to know.