Erectile Dysfunction ED NPT. To cure it?

Hello All, I am a 28 year old male, weigh 78 kg, and am 179 cm tall.  I was operated  for a 6 cm diameter cyst at Groin (Inguinal Region) on the left leg when I was 11 years old. I haven’t experienced morning wood or nocturnal penile tumescence (NPT) for several years. Occasionally, about once every two months, when I haven’t masturbated, I experience a nocturnal emission (wet dream) upon waking up. During sexual interaction, I can achieve an erection, but it’s not hard enough for penetration, and after a few minutes, I ejaculate. This can happen 5-6 times over the course of 8-10 hours of sex / foreplay. Could someone please help me with what can be the issue/medical problem here or how to cure it? Thank you and hoping to get some help! Regards