One part of the human Jesus's mission was to reveal the existence of the Father to mankind.
In John 17:25 and Matthew 11:27, Jesus says:
O righteous Father! The world has not known You, but I have known You; and these have known that You sent Me.
Nor does anyone know the Father except the Son, and the one to whom the Son wills to reveal Him.
Speaking of the Father, John 5:37 and John 1:18 say:
You have neither heard His voice at any time, nor seen His form.
No one has seen God at any time.
Yet the Hebrew scriptures describe many instances of people talking with YHWH, including Jacob's claim: "I have seen God face to face", in Genesis 32:30.
None of this makes sense if YHWH was the Father.
But consider the belief that YHWH, the God of the Hebrew scriptures, was the pre-incarnate Jesus.
(See my answer to contradiction - How can John 1:18 say that "No man has seen God" when the Bible says that Abraham, Moses, Job and others have? - Biblical Hermeneutics Stack Exchange.)
Now in that light, consider Isaiah 43:10,11:
… before me there was no God formed, neither shall there be after me.
I, even I, am the Lord; and beside me there is no saviour.
The "I", "Me", and "LORD" (YHWH) are all referring to the pre-incarnate Jesus.
So (in retrospect), this verse is simply stating that Jesus, and only Jesus, is the Saviour of mankind.
It is also confirming that both the Father and the Son have always existed and always will exist.
But all that is something that Christians already know.
And now in light of that, consider Titus 1:3,4:
… according to the commandment of God our Saviour;
… Grace, mercy, and peace, from God the Father and the Lord Jesus Christ our Saviour.
The Father and the Son are each worthy of the title God.
Working together, both are saving mankind, though it is the Son that carries out the necessary action.
This is similar to how, in John 1:3, "All things were made by him[the Son]; and without him was not any thing made that was made.", which certainly doesn't mean that the Father didn't create the universe too.
The Father has always remained in his Heaven, and it won't be until the end of the Millennium that he enters the physical universe.
… shewed me that great city, the holy Jerusalem, descending out of heaven from God, Rev 21:10,22; 22:3,4
And I saw no temple therein: for the Lord God Almighty and the Lamb are the temple of it.
… the throne of God and of the Lamb shall be in it …
And they shall see his face; and his name shall be in their foreheads.