Universalism - all humans will be saved - does not address the matter. Some universalists think so.
Col.1:16 For by Him all was created that are in HEAVEN and that are on EARTH, visible and invisible, whether thrones or dominions or principalities or powers. All was created through Him and for Him.
20 and by Him to reconcile all to Himself, by Him, whether on EARTH or in HEAVEN, having made peace through the blood of His cross.
Phil.2:9 As a result God exalted him and gave him the name that is above every name,
10 so that in the name of Jesus every knee will bow —in heaven and on earth and under the earth—
11 and every tongue confess that Jesus Christ is Lord to the glory of God the Father.
For then must he often have suffered since the foundation of the world: but now once upon the end of the eons hath he appeared to put away sin by the sacrifice of himself. (Heb.9:26)
The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world. (Jn.1:29)
When all is subjected to Him, then the Son Himself also will be subjected to the One who subjected all to Him, so that God may be all in all. (1 Cor.15:28)
Ephesians 1:10 as a plan for the fulness of time, to unite all in him, in heaven and on earth.
He who was seated on the throne said, “I am making all new!” Then he said, “Write this down, for these words are trustworthy and true.” (Rev.21:5a)
John speaks of “every creature” & to emphasize this again he repeats “and all that are in them”:
Rev.5:13 And every creature which is in heaven, and on the earth, and under the earth, and such as are in the sea, and all that are in them, heard I saying, Blessing, and honour, and glory, and power, be unto him that sitteth upon the throne, and unto the Lamb for ever and ever.
This worship (v.13) uses the same worshipful words as the redeemed of vs 9-10 use in v.12:
12 Saying with a loud voice, Worthy is the Lamb that was slain to receive power, and riches, and wisdom, and strength, and honour, and glory, and blessing.
All this being in the context of salvation - “the Lamb that was slain” (v.12 & 13).
“If God doesn’t save Satan, is it because He can’t or doesn’t want to?”
“Is anything impossible for the LORD?” (Gen.18:14)
Jesus looked at them and said, “With man this is impossible, but with God all things are possible.”
For nothing will be impossible with God."
being fully persuaded that God was able to do what He had promised.
Now to the One being able to do exceedingly above all things that we ask or think (Eph.3:20a)