Pick Fei-long. Easy to play, great footsies and your game plan most of the time is just to push your opponent to the corner and control space. Arguably the best ground game out of all the characters and not many real bad match-ups. Also great wake-up options and easy’ish combos. Simple and effective tactics like buffering rekka from jabs; st. LP canceled into command throw in the corner; controlling space with LP Rekka; and good high-low mix-up since he has a chainable cr. LK and one of the best overheads in the game.
Probably the most “pick up and play” character in the game. Just look at a few matches from Fuudo, Gackt, Mago and Momi from youtube and play him for a couple of weeks and you should be able to compete at your local tournaments.
I’m not saying it’s going to be easy to win with him but he is definitely the easiest to pick-up because he’s just so solid through and through.
Other choices are Honda, Adon and Balrog. I think all of these are harder to use effectively than Fei-long though since they have certain things you need to learn that are harder execution-wise, except maybe Balrog. Adon has instant-air jaguar kick which will take a lot of practice to do consistently and with Honda you need to learn how to do Hundred handslap-combos which requires a lot of practice as well.