Make me undertsand (christains)

I’ve always thought ,Was Qoheleth (in the book of Ecclesiastes) ,King Solomon.

Qo•he’leth translated into “the congregator”.
Greek Septuagint give the book the title of Ek•kle•si•a•stes meaning a member of ecclesia(congregation; assembly) from which derived the English name Ecclesiastes
Though Solomon is not specifically named several passages are quite conclusive in establishing him as the writer.the congregator introduces himself as "the son of David"who “happened to be king over Israel in Jerusalem”.this could only apply to King Solomon, for his successors in Jerusalem were kings over Judah only.
Moreover, as the congregator writes:“I myself have greatly increased in wisdom more than anyone that happened to be before me in Jerusalem, and my own heart saw a great deal of wisdom and knowledge.”(1:1,12,16).this fit Solomon.

Yes, clearly this is solomon speaking

Yes, it is Solomon Kohelethu David. You also have three names, right?