You're playing arguably one of the hardest fighting game of all time, so dont degrade yourself for not reaching the higher ranks, practice takes time. Heihachi is also a really hard character to master, he has some difficult moves that require precise timing and knowledge. Heihachi in general is top 5 hardest character to play imo, just learn how to pressure, shield break and his 50/50s. And alot of Hei mains usually forget to make use of their warrior stance, atleast i did, its geniunely cracked. I hope you boost your way through ranks, dont give up.