You could probably rule out Klinefelter syndrome, as your FSH and LH are pretty much mid-range, whereas I'd expect them to be high if you had it. But the only way to try would be to get a Karyotype done.
If your testes are as small as you say, then it might be worth doing a fertility test.
How is your body proportioned? Klinefelter syndrome tends to result in longer limbs, gynecomastia, wide hips, and narrow shoulders.
As for TRT, your total testosterone and calculated free testosterone (11.5 ng/dL) are at a level above where a physician would prescribe it. Your LH and FSH are mid-range, so you're not suffering from subclinical hypogonadism.