From where should one enter into a state of Ihram for Hajj this year, if traveling from Egypt to Taif?

The prescribed way is to enter into a state of ihram from the miqat, not from Cairo Airport or Taif. The Sunnah is to delay entering ihram until you pass by the first miqat, whereupon you enter ihram from it. The miqat for the people of Taif is Qarn al-Manazil. One must enter ihram from the first miqat a traveler passes through. If one enters ihram before reaching the miqat, it is permissible, but it is contrary to what is most virtuous.