The action was enough to keep me reading, but I started reading this in 2017, and the series has taken too many breaks. I mean, it's a monthly manga, and they're milking it with fillers. Many important details are lost because the author releases them in interviews or even decides to contradict himself (for example, he delays deaths or adds a side chapter based on his discarded pictures).
The quality is still great, but I dislike the unnecessary elements being added (the surviving dragon that attacked Leonica out of nowhere, Slime constantly being enslaved, making Quimera weak or strong arbitrarily, etc.). All these are examples of places where they could've advanced the plot, developed less-seen characters, or just added a random filler. They usually bring back already-finished plots that don't add anything new, just to leave a random flashback or an incoherent scene about the bad guys.
I mean, that isn't enough to keep me interested, especially when half the action panels are technique names and barely show continuity in the action. In one scene, Ragna gets a hole blown on him, and then he is attacking with a different background. Did he dodge, parry, or regenerate?. With Kamui, fights started having grander and grander techniques without conveying what the characters were doing properly. I liked some of those chapters, but Ragna's techniques were supposed to be precise and the kind of stuff someone fighting without support would do.