You basically explained the cause of this by yourself...
I can understand what you are trying to say, because at first my ground game was horrible as well and once the fight went to the ground, I'd lose 9 times out of 10. I'm only level 22 at the moment and i haven't been lucky with the cards I've been getting from packs (for ground moves).
What i did to improve this:
-I made a single player career fighter that was almost identical with my ultimate team guy.
-Went in the practice ground drills for hours and just build it up from easy to hard. Just make an analysis from what every transition will offer you in the next position and vice versa. Do not underestimate the importance of STAMINA!!!!
-After some practice, start playing career on beginner and try to dominate fights with the things you have learned. If things get too easy (which should be kinda fast if you did some proper practice), just put the game on a higher difficulty.
I can tell you from my personal experience that i've been winning a lot more fights after I did this, so give it a try and see if it helps for you too.
