https://www.blueletterbible.org/faq/don_stewart/don_stewart_79.cfm
Summary
The reason Lucifer has been understood to be a proper name of the Devil has to do with the Latin translation of the Hebrew term Helel. This word was understood, by some, to be a proper name for the king of Babylon. It means "light bearer," or Lucifero in Latin. The Latin title became a popular name for this evil figure. When the King James translators rendered the Hebrew term into English, they kept the popular term "Lucifer" for the Devil.
We may not know the original meaning of the word helel that the author used for that certain context.
Helel means " a shining one". This is well known.
It just seems that the authors intended meaning for "helel" is debatable. I dont know what i believe about that personally.