Is it obligatory for one who has practiced sodomy and fornication, and repented with sincere repentance, to present himself for the execution of the prescribed punishment (Hadd)?

You must regret what you have done, for the door of repentance is open to everyone. If you repent with sincere repentance, Allah will accept your repentance. As long as Allah has concealed your sin, do not expose His concealment. You are not required to seek the implementation of the Hadd punishment upon yourself; rather, your repentance is sufficient between you and Allah.