I have the same feelings. Except I abandoned ship pretty quickly.
I use Marshmellow fondant on cookies. Did it for a while so then I tried a cake. Except I tried a different recipe. It was a chocolate fondant recipe. I did it once, the very first time...perfectly. No problems. Tried again...NOPE. Nothing I did made it work.
I also had a serious case of beginners luck years ago. I made a 3 tier (using a floating stand - so definitely cheating on the stacking issue) and covered each tier with wilton pre-made fondant. Gross I know. But they weren't gonna eat it anyway. It was just for looks. Amazingly enough, I covered all 3 tiers perfectly. The one tier was HUGE too.
But, since I had so much trouble with the chocolate fondant I have yet to try to cover a cake with regular flavored fondant. I've seen many people use the marshmellow fondant with success. It's pretty cheap so messing up isn't a huge issue.
I share in your fondant woes. I'm sure if I took the time to keep working at it, it would get better. So - just keep trying. Maybe even set up several small cakes & do like 3 in a row. Or, with different fondant recipes. Maybe that's it.
I hope you figure it out!