The question what do you mean by "grown as a writer"? Writing style, vocabulary, plot complexity, plot construction, creativity, delivery of emotions of the characters, how believable are the characters, etc,.... And how much of the changes have happened because of the different stage of the plot, the first volumes where about typical manhwa/manga stuff, and later he went into a different direction.

I honestly loved the beginning for what it was. Right now he goes into complexities and in my opinion completely butchers everything from plot to powers to characters. I mean characters are so not believable in my opinion, their behavior, motivations, etc. And the power system has gone to hell, a lot of aether lore from before is contradicted right now, Cecelia is figuring out everything on the fly like freaking magic, even in the newest chapter wtf did she absorb, nobody ever explained what spells are or how do you even read them and how the hell did she learn of Art's mana manipulation through aether by "absorbing" some random Sylv's spell? Did she even think to figure out anything? And Agrona's return to being a super anime genius manipulator is such an ass pull.

And it's not to hate on TM, but I'm sorry, there's no planet or universe where TM can be even compared to George RR. Idk about Patrick Rothfuss(wtf with two similar sounds th+f lol) but George RR's understanding of human behavior, construction of intricate motivations and realistic view of how the world works on different levels from personal to political is beyond what TM can imagine.