Do you really think Isaiah under divine inspiration would quote folklore? Whether or not you believe this to be about Satan, you do realize Satan rebelled against God. Rebellion was one of our sins in the garden.
However, there really isnt much written in our texts concerning the angels, other than their interaction with us. We dont know about the war that is taking place in Heaven between the angels, just that there is a war. As we are told, we fight an unseen enemy. We also know that "hell or lake of fire" was not intended for man, but was made for the angels (bad angels). Matthew 25:41 states, " Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels"...
There are two TANKH scriptures I believe to illude to Satan: Isaiah 14 and Ezekiel 28. They do speak of Babylon and Tyre, I agree. But I still believe them to illude to Satan/Lucifer.
God uses shadow pictures and parables to relate spiritual things to us. Just look at Nicodemus who was so knowledgable in the Torah:
John 3
There was a man of the Pharisees, named Nicodemus, a ruler of the Jews:
2 The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him.
3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
4 Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?
5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.
6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
7 Marvel not that I said unto thee, Ye must be born again.
8 The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit.
9 Nicodemus answered and said unto him, How can these things be?
10 Jesus answered and said unto him, Art thou a master of Israel, and knowest not these things?
11 Verily, verily, I say unto thee, We speak that we do know, and testify that we have seen; and ye receive not our witness.
12 If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you of heavenly things?
13 And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven...