Social media engagement - of interest to authors!

So, I have a number of social media platforms where I've built up a significant following over the past 14 years as an author. The question is: how useful are they for getting the word out? Yesterday I spammed the cover reveal for my next book, Daughter of Crows , over all my platforms. I know that they all bury any post with a link these days - they want you looking at Twitter/Facebook/Threads…