[BookCat]

If you have an up and running youtube channel, place a preview of your book on it, maybe reading part of the first chapter. Invite people to comment and to mention if they would be prepared to receive review copies to review. Be prepared for trolls and some very nasty comments.
There are many booktube channels who depend on freebies, sometimes they review them (in a video) sometimes they don't, but they often mention that they've been sent the book and read the blurb. Most of them prefer paper copies to ebooks. Perhaps pm the booktube channels to ask if they would like to receive an ebook version, also sending them information such as a very brief synopsis/blurb. Chose only channels who review your type of book. Ask them if they would mind leaving written reviews on Amazon/wherever also.
The response will be sparse and patchy.