Why does Hashem not desire a Zevach?
Rashi: Chatas does not come for Mezid.
Radak: I know that You desire more a broken heart. I repent with a broken heart in front of You! The purpose of Korbanos is to break the heart, and eradicate bodily desires from it. Burning the Emurim resembles burning animal desires.
Why did he say "v'Etenah"?
Rashi: If You will desire, I will give it to You.
Why does it say "Lo Sachpotz" and "Lo Sirtzeh"?
Malbim: Chefetz is of the Nefesh. His desire and the leaning of his Nefesh desire what is pleasant or beneficial. Ratzon is mental; he is pleased with what is good. Shelamim is l'Ratzon. Hashem has no Chefetz or benefit from it, but He desires it, for via it, man recognizes his Creator. It makes Shalom between Yisrael and Hashem. Olah atones for Bitul Aseh, or Lav ha'Nitak l'Aseh. Hashem has no Chefetz for it, and not even Ratzon - He prefers that man not sin and not need Kaparah! "V'Nirtzeh Lo Lechaper Alav" (Vayikra 1:4) is after he sinned. (Then, Hashem desires the Korban.)
