How to acquire English to the native fluency?

What can I do to inhabit the English language more? I moved to America at around age 14–15. Overall a quick learner. Now I’m 28 and still I find that I’m nowhere near the native level.

Over and over again, I’ve found that my English comprehension can be mechanical or literal. For example, I would hear a joke in English and not laugh, while hearing the same joke in my language would bring me the totality of the absurdity of that joke, and I would laugh. This frustrates me because I would at times miss the “whole picture” of whatever I happen to be reading, or especially during socializing.

Sometimes also, when reading aloud, I would focus on the pronunciation, my reading, and I would miss the content. I wouldn’t know what just happened, but those who were listening to me would.

Other times, when speaking and thinking simultaneously, I would focus on my thoughts and my English accent would be terrible. On a bad day, I think I’d come off as stuttering.

There’s also a certain elusive distance when speaking English as well. My English self is almost a different person.

When visiting my birth country, I’d be surprised by the ease of my native language use. I did not have to try at all, and everything was so immediate to me, so easy and natural like using my hands. I would be the one who corrected others, “That just doesn’t sound right, the way you say it.”

If you have had any experience successfully acquiring a second language, what would you suggest? Is this something I would see a speech pathologist about? A language specialist? I’m very frustrated with myself.

Thank you all.