5. Can I ask God for death?

No, this is completely forbidden according to Islamic teachings. This has been alluded to in the following hadith:

Sad ibn Ubaid narrated that the Prophet once said, ‘None of you should long for death, for if he is a good man, he may increase his good deeds and if he is an evil doer, he may stop the evil deeds and repent.’ (Sahih al-Bukhari, hadith no. 7235)

Hence, the longer you live, the more opportunities you get to do good deeds, or repent if you have committed any bad ones. Keeping this wisdom in mind, one should always pray for well-being and happiness and not anything negative. According to the creation plan of God, the hour of death for every individual has been appointed by God Himself. We should accept our natural time of death, as God knows what is best for us.