What is "ha'Elokim ha'Adirim ha'Eleh"?
Radak citing Targum Yonasan: The word 1 of Hashem, whose deeds are great. These are His deeds
Radak citing his father: "Ba'Midbar" is like "u'Midbarech Navah" (your speech is beautiful).
Why does it say "Elokim ha'Adirim" (plural)?
Radak: In Nochri language, they use the plural for other 1 Elokim.
Malbim: Refer to 4:8:1:2.
I do not know why he said 'other'. Perhaps he means, any god other than the one they revere. Elokim is sometimes plural in Tanach, e.g. "Elokim Chayim" (17:26, Devarim 5:23. - PF)
What is "b'Chol Makeh ba'Midbar"?
Rashi: It is at Yam Suf.
Rashi citing Targum Yonasan (of "ba'Midbar"): He did wonders for His nation in the Midbar.
Rashi citing Sifri: Different groups said the words in this verse 1 . The Kosher Pelishtim said "who will save us from this awesome G-d?!" Resha'im said "this is Elokim who struck Egypt with every plague" - He has none left 2 !
Refer to 4:8:1:1*.
Malbim: He struck with all kinds of Makos, also in the Midbar. (His strength and domain of his power are not limited.)
Radak: We find like this - (Devarim 25:18) "v'Atah Ayef v'Yage'a" refers to Yisrael, and "v'Lo Yarei Elokim" refers to Amalek.