I think Amy Corwin’s Second Son Inquiry Agency books are probably self-pubbed (Fireside Mysteries?), but in any case, I’ve read and enjoyed all four of these historical Regency period mysteries. They probably drift over into romantic suspense, but Corwin also writes some straight-up romance, and these aren’t that, so I’m putting these ones in with the mysteries!
Either way though, the first book, The Vital Principle, is free right now at Kindle US and UK, so you can just try for yourself and see what you want to call it! And if you like it, the other three books are usually pretty reasonably priced too, so you don’t have to spend a lot for them either. And they are all KU, if you have a KU membership…
Another Amy Corwin freebie…
The Unwanted Heiress, apa I Bid One American (!!!), is the first in Amy Corwin’s Archer Family series. This one is IMO also more of a romantic suspense book, just like the Corwin freebie in the OP, even if it’s formally called a romance. (There are, after all, multiple dead bodies ?…) But, of course, YMMV…
In any case, it’s free right now at Kindle US and UK, so you can just try it. And also as with the other one just now, the rest of the series is pretty reasonably priced if you like the freebie.
Kindle US: https://www.amazon.com/dp/B00BSFFNTY/
Kindle UK: https://www.amazon.co.uk/dp/B00BSFFNTY/