Did one of the cherubim guarding the Garden of Eden become Satan later?

I don't know, but there is some chance that it could be true.

Genesis 3:

24 He drove out the man, and at the east of the garden of Eden he placed the cherubim [Cs] and a flaming sword that turned every way to guard [H8104] the way to the tree of life.

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Cs guarded or protected the tree of life.

Ezekiel mentioned a creature (C1) in Eden, 28:

13 You were in Eden, the garden of God; every precious stone was your covering, sardius, topaz, and diamond, beryl, onyx, and jasper, sapphire,b emerald, and carbuncle; and crafted in gold were your settings and your engravings. On the day that you were created they were prepared.

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C1 was in Eden.

14 You were an anointed guardian [H5526] cherub.

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C1 was a guardian cherub. Was C1 one of the Cs?

C1 was in Eden. C1 was a guardian cherub. There is some probability that C1 guarded the tree of life.

I placed you; you were on the holy mountain of God; in the midst of the stones of fire you walked. 15 You were blameless in your ways from the day you were created, till unrighteousness was found in you.

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C1 could be the serpent (Rev 20:2) who tempted Eve to eat from the forbidden tree.

16 In the abundance of your trade you were filled with violence in your midst, and you sinned; so I cast you as a profane thing from the mountain of God, and I destroyed you, O guardian cherub, from the midst of the stones of fire.

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C1/Satan was cast/thrown down from heaven.

Did one of the cherubim guarding the Garden of Eden become Satan later?

There is some probability of that.

See also The changing role of satan