I understand what you mean seeing as I'm kinda in the same boat. I'll be honest this is a hard position t be in. I know some others would just say, "welp if its your dream then you have to do what you have to do" Which kinda translates to drop your own style and do this other one( or do what like on the side but for work you gotta do things another way). If the splash art style is not for you then you might have to think of something else but I know its not as easy.
What studio or studios would you like to work at?
From that answer, you can try to push one painting to that level of quality and see if its fun. You'll really have to think about it. Maybe try doing 3.
AS of right now I would say your kinda close to the old Riot games splash art style. Backgrounds aren't super detailed and mostly painterly and the characters ofc are the main focus(backgrounds are still blurred but a little more detailed than older works in my opinion). Pushing yourself to current Riot games(only using riot since you've done lots of fan art) you'll really have to push your material definition as well as having less visible brush strokes. Of course in some arena's you'll see some brush strokes but they seem to be contained in clean shapes. Another thing I noticed with riot splash paintings is that they seem to be using some kind of sharpen feature. I believe this is something done towards to end of the painting from another artist I heard talking about this. Posing and perspective is another thing you can focus on. The last sketch you did reminds me of the "Battle Academia Katarina" piece done by Atey Ghailan. So maybe you can make that sketch into a bigger painting. The last thing you can work on is your lighting which I notice your already doing. You seem to be moving in the right direction here.
You have to honestly ask yourself if the dream you have is really what you want and if it is, go for it. Find your fun in making those kind of detailed splash paintings.
This of course is just my opinion. Do what feels right for you. This is something I tried and now I'm moving in another direction that is hopefully better for myself.
Sorry for the essay answer. this is something I can talk about for ages I feel lol There were other things I could've added but I was like this is getting to long.