It's pretty good, but a little awkward. Perhaps a better way to say it is: "Even doing all that you have mentioned, it takes years to get fluent enough."

I like Ian's version, although unless there is some context that you have not provided the "enough" at the end of the sentence makes it feel like something is missing. I would say it like this: "Even doing all that you have mentioned, it takes years to become fluent."

I'd say it like this: "Even after doing all that you have mentioned, it still takes years to get fluent enough."

I think it will be better if you said with doing all that you have mentioned. it still takes years to get fluent enough