Ypso - your last paragraph - pure GOLD - if word got outside of this known circle (here), it would catch interest with certain readership that won't try Mistwraith or any of my titles because they related to the collaboration and 'presuppose' my work is lighter fare, like Feist's. There are authors working for adult audience, but they are harder to find, or less mentioned. I see posts in r/fantasy all the time, for folks LOOKING for more adult fare and all they are hit by suggestions that (how I WISH) included Light and Shadows from readers in the know. Also many read the first 3 books and there is no 'buzz' that the later series opens out the way it does. Social media could help these books, but there are not enough readers (yet) on the mark with them when the topics arise that fit.
For a more adult read, meantime, if you have not read Kay or Carol Berg's Lighthouse Duet that starts with Flesh and Spirit, I do recommend those.