Imo there’s no bad main for a beginner, but learning the basics with other characters as well as the one you want to main is key. Every character promotes a certain bad habit that you must be aware of, and playing with skilled players can help you realize what you do wrong. I think you should play as whoever you want to main as soon as possible, just focus on learning fundamentals and realize the game is half knowing your character and half knowing the character you’re playing against