There could be a possibility that it’s more of a physical limitation for you, I actually had trouble pronouncing a lot of c, p, I words, there were a few more, but a speech therapist said it might be due to my tongue tie. I opt to get it cut, and I was surprise that words I had trouble with start easily rolling off my tongue. Not to mention it helped with a lot of other things too, like my headaches. Some people have severe tongue tie and some not so much but it’s more genetics. Simple procedure like getting a tooth pulled. You might want to look into that, it frees up the tongue. Sim