Egyptian heiroglyphs were not an alphabet, even if they had alphabetic elements (in addition to pictographic ones). Scholars generally agree that proto-Sinaitic was the first alphabet, and all subsequent alphabets used today are either direct descendants or directly inspired by it. https://en.wikipedia.org/wiki/History_of_the_alphabet
As per the Wikipedia links, it's generally considered by scholars to be the origin of all alphabets and an early alphabetic script. Abjad is a term invented in 1990 to distinguish early alphabetic scripts without vowels from later scripts with them. Effectively every scholar agrees that Canaanite/Aramaic/Hebrew/Arabic are alphabetic systems (while also acknowledging them as abjads).
