We can all speculate and by taking a text out of context come up with possible answers, but let's use all the scriptures applicable.
First, let's study what is written about Satan, the Devil, the dragon, the ancient serpent. These titles are given in Rev. 12:9, the last book of the Bible.
Notice, "Lucifer" or "Son of the morning" is not listed.
Facts: Satan never called an angel, even though we read in 2 Cor. 11:14, NIV, "And no wonder, for Satan himself masquerades as an angel of light."
But "angel" in Greek means "messenger". It doesn't mean that Satan is an angel, a spirit being who is either a messenger for God, or for Satan.
I know from those passages in Ezek. and Isaiah many teach that Satan was first created perfect until pride came into his heart, and he was determined to be like the Most High, and this was his downfall; but I don't see it that way.
I believe God is the Sovereign Lord of the universe, and created all things through the Word, His Son, Christ Jesus. And because of His great love for all his creatures, He has planned to show forth how great His love is, by being their Saviour. And, to need a Saviour, man must be lost, and that is what happened in and through Adam.
The name Satan means "adversary". He is called a murderer (manslayer), the hater, a liar, an opposing spirit. IMO, he was created as the "adversary" needed in God's plans.
More later, Bick