Medically speaking, my doctor explained that the baby's gender is decided solely by whether an X or Y chromosome sperm fertilizes the egg, which is a 50-50 chance. No timing or diet can alter this, so just focus on your fertile window.
Honestly, gender is totally a matter of chance and we cannot choose it. Focus on tracking your ovulation so you can conceive a healthy baby, that is all that truly matters in the end.
There is no scientific way or specific timing after your period to conceive a boy, as it is completely random. Please consult your gynac for safe conception planning rather than believing in these myths.
Having faced complications, I can tell you that a healthy baby is the only blessing we should pray for. There is no day that guarantees a boy or a girl, so please consult a proper doctor for healthy conception advice.