A Clear Quran

This particular expression occurs twice.

S 15:1  Alif lam mim. Those are the signs of the book and of a clear quran.

Apparently alif, lam, mim are the signs of an unnamed book AND of a clear quran.

The Perspicuity of the Quran and It’s Mysterious Letters

'The Book'

A Clear Book/Clear Signs

A Quran?

S 36:69 And we did not teach him poetry nor is it appropriate for him. It is nothing but a dhikr and a clear quran

'We', whoever they are, didn't teach him poetry and it wasn't appropriate for him. He did however employ a poet. 'It', presumably quran, is a dhikr and a clear quran.

Shurayh said, "I ask 'A'isha, may Allah be pleased her with, 'Did the Messenger of Allah, may Allah bless him and grant him peace, recite any poetry?' She said, 'He used to recite some of the poetry of 'Abdullah ibn Rawaha:

https://sunnah.com/adab:867

For some reason, the translator has omitted the quotation.

وَيَأْتِيكَ بِالأَخْبَارِ مَنْ لَمْ تُزَوِّدِ‏.‏

'And he brings you news of him who did not provide.'

Islam and Poetry: Muhammad’s Love-Hate relationship with Poets

Dhikr