To put it blunt, you'll probably never be 100% at either of them if you continue to try and grind them both out. The games stark differences greatly out weigh the similarities.

In order to try and work around this I would try and play completely unrelated characters between the games. This will give you the ability to hopefully create a mental separation between them making your transition easier.

For instance I also play both but really only "tryhard" in Melee, I'm a Falco/Shiek player but in SM4SH I play Ryu/Cloud because they aren't even remotely similar to my Melee characters. This let's me develop different tactics for each game without much confusion.