If you dont care about winning i believe i can give advice to anyone in your situation. Play who makes you hype to get on the game every day. For me its brainiac, something about him and the character itself is so dope and i love boss characters. But ill be at work sometimes thinking about new setups and ways to get in and how i can make some of his setups safe and blah blah blah. Point is, the character is so fun to play i barely care if i lose, nd honestly that attitude helps me win more. That being said ill give you a couple suggestions for your potential main. Again this is based on the idea that you wont care that much that you lose, at least while learning the character.
Joker - I personally love this character. I think hes got great range, great combo potential, amazing mixup and obviously he still got them sext chattering teeth for setups. He does have DECENT zoning, at least enough for what you want, but his frames are kinda shit. Startup on anything but his teeth and gunshot are ass and his forward advancing mid doesnt really advance much so some of his potentially really good combos and setups are a lot harder to hit. However theres really nothing like putting someone in the blender of teeth+overhead 3 on wakeup 3 times in a row for a basically free lifebar of they dont know what to do
Poison ivy - she has everything that you want and has pretty good damage on some things. Her advancing normals are crazy albeit a little more button heavy than some characters but to top it off shes got a shader that makes her ms mary jane (purple/green) annnnndd to top it off you get a pet. Thats the best part you can name that little snot monster. I will call him squishy, and he will be mine, and he will be my squishy.
Darkseid - now this character can easily get you wins with basically zero experience, however he is so fucking cool idegaf how minutely upsetting he can be to play against. Hes such a boss. He pimps/bitchslaps people, holds his hands behind his back, has dope ass projectiles, AAAANNNDDD you get to name not one but 3 count em 3 pets. Go ahead enjoy it, i call mine Earl, samsonite, and wilson. Besides all the clearly awesome aesthetics, he has amazing normals and mixups. A rediculous teleport, huge damage scaling, great projectiles. Hes just a littttllleee slow. But kind of like akuma in sf. Stay on the offense.
Anyway hope this helped anyone who reads it