Am I the only one who thought the action stuff was fun? The premise is literally "the world's best fighter and killer becomes a maid". IMHO, I feel that having some over the top action sequences really sells the idea better, especially when there are manga out there that try to make a character "the world's best ________", then either have a really underwhelming display of their abilities, or straight up show nothing of what they are supposedly the best at. At that point, why even have them be "world's best"? I far prefer this setup. Show how strong she is, add some fluff, show how much she has changed, take time to build on the snippets of backstory, big display of her strength to show that she's still the best and even stronger than initially shown, resolution (upcoming). We got a full view of the dynamic between the sisters, their past, and their reconciliation. Personally, I feel satisfied with seeing the resolution, but it was supplemented by how author took time to flesh it all out.
Besides, if nothing else, I just think that it's cool to watch a beautiful ex-assassin girl take down a mech with a big sword, while wearing a maid outfit (not mobility-friendly). Sometimes you just gotta enjoy what you're watching/listening to for where it is, not for where you want it to be. And consider this: since the action stuff took a while, now the return to fluff feels all the more gratifying, no? And we have no more urgent questions that warrant another fluff interruption for another long while. Very cool.