I dont see the problem.
For the tournament, take the input device, on which you can play the best.
In general, its recommend for fighting games, to play on a arcade stick, cause thats, what the games are designed for !
Its quite hard to get used to it, after playing on a pad, every move seems so damn slow.
Some make it in a view weaks, some need a view months to get fully used to it.
But after you got it, u will never ever switch back to a pad, believe me, thats the general consent, noone will disagree.
Just use the training mode. And do the motions, hadouken, 100x to the right. 100x to the left etc. try this with every move. It takes so long for the brain and the nerves, to build up the so called “muscle memory”. Practice it slowly! Then after time, make it faster. Thats exact the method, to learn an instrument btw. same concept.