Word of advice about simple art styles. There is a difference between keeping it simple and bland especially when you're trying to entice your audience. Comics and cartoons are a visual media so they way you design your characters and the colour palette matters. A lot. As does the genre which is something I learned while drawing my own comics.
Super simple doesn't work for everything unless it's the exception not the norm like Adventure Time or Gravity Falls (great series by the way). And even then, those cartoons have moments where they have to fill in details visually so the situation can be taken seriously.
Now if you're trying to do a kid's show or sitcom like the Simpsons, it's the reverse of which cartoons like the Boondocks are the exception with having tons of details and being a hit while most of the time, keeping it simple is more likely to win people over.
I'm not saying you shouldn't try to draw your comic anyway in your style, but if you're going for action, make sure it does at least have hard edges, characters designs and the right of colours to match. I mean, even Matt Groening gave his action series Disenchantment an edgier harder look than the Simpsons which is a sitcom.
You can tell it's the same artist, but one is sophisticated with darker tones and more shading. Also, the background is drawn in a line-less fashion or even coloured lined are used here and there.
Meanwhile, with the sitcom the Simpsons, it's bright, the shading is minimal especially on the characters, the lineart is 95% black and the details are very minimalist. Plus, everything is rounder and cuter.
It's very clear what each cartoon is trying to be, what its genre is and which audience it is trying to win over. Keep this in mind when making your comics. it's ok if you can't draw like this. Neither can I.
But if you're going for action adventure while also aiming to draw in a mature crowd, this is not going to work. You need to practice or find an artist who can bring your designs to life if you can.
And remember, it's ok to have limits. If you can't make it happen with a comic, make it happen with a book like Game of Thrones, Lord of the Rings and Harry Potter. We're not all cut out to create action comics.
Plus, you can still present your book to animation studios as a manuscript. Lots of cartoons beloved, shows and films were adaptations of books.
Try everything and never give up.