Murder was in Pharaoh's heart is all you need to know.
But not only that, God's Judgments on Egypt were to show how impotent Egypt's so-called "gods" were, i.e.
Plague #1: Water into Blood
Egyptian god attacked: Hapi – The god of the Nile
Plague #2: Frogs
Egyptian god attacked: Heka (Heqt or Heket) – The god of fertility
Plague #3: Lice
Egyptian god(s) attacked: Geb /Horus – The god of the earth
Plague #4: Flies
Egyptian god attacked: Kheper (or Khepri)
Plague #5: Death of Livestock
Egyptian gods attacked: Apis: (Sacred Bull); Hathor: goddess of protection
Plague #6: Boils
Egyptian gods attacked: Imhotep (physician god); Thoth (Magic and healing); Isis, goddess of medicine
Plague #7: Hail
Egyptian god attacked: Nut – The sky goddess
Plague #8: Locusts
Egyptian god attacked: Seth – The god of crops
Plague #9: Darkness
Egyptian god attacked: Ra – The sun god, their primary god
Plague #10: First Born Killed
Egyptian gods attacked: Pharaoh (He was considered a god and his first born son would become a god after him); Bes – Protector of Children; Aten – Symbol of life.
Pharaoh's gods couldn't save Egypt from the plagues.
The Ten Plagues of Egypt