Obviously, Egypt is not Kel! What does the verse teach?
Radak: They cannot help if Hashem does not want. Everything is in His hand - good or bad that will come to him. A man says, and does not do; he speaks, and does not fulfill.
Radak citing Targum Yonasan: It is not Kel, and not an officer.
Malbim: Their adversary is Hashem, and the weapons in His hand are angels of Ru'ach who do His will. If you seek help to nullify His words, also your help must be Kel, like Him, and its weapons must be Ru'ach, like His!
Obviously, their horses are flesh, and not Ru'ach!
Radak: Yisrael trusted also in [Egypt's] horses - also they are flesh and not Ru'ach, i.e. an angel. "Sheker ha'Sus li'Sshu'ah" (Tehilim 33:17). How can Egypt help them? They cannot help themselves, for Hashem will put [Ashur] on them!
Malbim: Refer to 31:3:1:3.
Why does it say "Yateh Yado"?
Rashi citing a Midrash: Hashem supports everything with His hand. When He tilts it, they fall, like one who holds something in his palm. When he tilts his hand, it falls.
Rashi citing Targum Yonasan: He will lift the hand of His strength.
To whom do "v'Chashal Ozer v'Nafal Azur" apply?
Radak: "V'Chashal Ozer" refers to Egypt; "v'Nafal Azur" refers to Yisrael.
Why does it say "Yachdav"?
Radak: Melech "Ashur Shevet Api u'Mateh? Zami" (10:5). Also Egypt, Melech Ashur plundered 1 and took them captive. He came against Yerushalayim with those captives and spoils. About this it says "Yegi'a Mitzrayim u'Schar Kush?" (45:14)
We explain based on Kli Paz' text of Radak 'Gam Mitzrayim Bazaz v'Shavah?'