O doubt Tyre had an exceptional king or two. But this passage seems most obviously to be directed at Lucifer. He is called the prince of Tyre here. Ezekiel had a contemporary who also spoke of demonic influencers as princes (Daniel 10:20). And, if this passage in Ezekiel is indeed about Lucifer, then it opens our eyes to sin's very point of origin.
In the Bible, the sea can be an allusion to the population of the world (Revelation 13:1). Certainly Ezekiel 28:2 would fit into that category. At his fall, Lucifer was cast down to the earth, and by means of Adam's fall was evidently given temporary authority over the human race (Matthew 4:8-9). Through this process we see Lucifer acting as if he is divine, but Ezekiel declared him to be much less than that (Ezekiel 28:2). In his state of innocence, he had been wise. That lasted until he recognized how wise he was, then he became a fool. Dissatisfied with his station, he desired a share of God's throne.