I couldn't put Asunder down but I can't get past the first chapter of Masked Empire. (I don't know what the difference is. It just seems kind of ... political? Instead of interesting lore wise, with demons and such.)
I had exactly same issues, I could only make myself past first ME pages on my 3rd attempt. It's nothing like Asunder, in very many ways. I can't say 'it's a bad book per se, but it's definitely not my type of reading. Much less expressive descriptions, which are supposed to pass an impression to a reader. much more direct dry details (buttons, laces, gems, pearls, buckles etc). Much less believable emotions, much more politics.
I found it to be opposite, Asunder was good, but I felt The Masked Empire blew it away.
The descriptions were more detailed and immersive, the characters felt more interesting and memorable with their own agendas and desires, and it is one of the rare few times where I found the characters on both sides (in this case Celene and Gaspard) to be sympathetic and likable, for different reasons.
The plot was captivating and fascinating, the pacing was good, and writing-style was great, neither heavy or superficial. And there were a good mix of intrigue, characterisation, combat, exploring, dialogue, and emotional turmoil.
Further, the fighting scenes were absolutely superp, something I know from personal experience can be very hard to get right.
It may just be personal preferences, but I still consider it one of the best books I have read in a long time.