Ad by the author, who followed up by saying she is "the very best at marketing". Which must be true, because I absolutely went out and bought this book because of this ad.
The excellent news: Not only did I not regret it, upon finishing I went and immediately bought the sequel, and am now sitting on tenterhooks awaiting the third book.
The Queen of Ieflaria features alternating POV between the two main characters (and romantic interests), Esofi and Adale. Princess Esofi has been engaged to be married to Adale's twin brother since a very young age, in no small part to forge an alliance between their countries. Unfortunately, the brother in question dies shortly before the book begins, leaving Adale to take his place in the contract. At first unenthusiastic, Adale warms to the prospect almost immediately after meeting accomplished mage Esofi - only to be faced with competition from her grasping, power-hungry cousins. Esofi, meanwhile, must pick between the three of them, all while trying to figure out why the country she will so be queen of has so few mages, and, with help from the battlemages in her entourage, defending everyone in the capitol from dragon attacks.
Good, accessible high fantasy, with lots and lots of queer characters, including explicitly nonbinary characters (and gods!); no enby MCs yet, but I live in hope! To people who like dragons as things other than thoughtless killing machines, I promise that you will be satisfied by the time you get to the end. My only complaint is that the names didn’t always come naturally to my mental pronunciation, but that’s very minor on the scale of things. Also, like Shira Glassman, Effie Calvin is aiming to make the books possible to start from anywhere in publication order, so you don't have to read them chronologically for them to make sense (even though there's only two out so far).
The author's website is over here, with a map of the countries and a couple of free short stories - though Ioanna is very mildly spoilery for the second book, and The Gift is quite spoilery for the first.
Anyway, my brain has been on the fuzzy side for weeks now, so I'm going to leave it there, but definitely worth checking out if you like wish-fulfillment-y f/f fantasy stuff!