Do Jehovah's Witnesses have one Saviour or Two?

Jehovah’s Witnesses have only one principal Savior, Jehovah God. Jesus Christ is exalted as the “Chief Agent and Savior (Acts 5:31) because it is THROUGH Jesus that salvation is accomplished:

Savior - Insight on the Scriptures, Volume 2: Jehovah is identified as the principal Savior, the only Source of deliverance. (Isa 43:11; 45:21) He was the Savior and Deliverer of Israel, time and again. (Ps 106:8, 10, 21; Isa 43:3; 45:15; Jer 14:8)... When Jesus was on earth, Jehovah was his Savior, supporting and strengthening him to maintain integrity through his strenuous trials.—Heb 5:7; Ps 28:8.

Along with his role as Savior, Jehovah is also the “Repurchaser.” (Isa 49:26; 60:16) In the past he redeemed his people Israel from captivity. In delivering Christians from sin’s bondage, he does the repurchasing through his Son Jesus Christ (1Jo 4:14), Jehovah’s provision for salvation, who is therefore exalted as “Chief Agent and Savior.” (Ac 5:31) Accordingly, Jesus Christ can rightly be called “our Savior,” even though he performs the salvation as the agent of Jehovah. (Tit 1:4; 2Pe 1:11) The name Jesus, given to God’s Son by angelic direction, means “Jehovah Is Salvation,” for, said the angel, “he will save his people from their sins.” (Mt 1:21; Lu 1:31) This name points out that Jehovah is the Source of salvation, accomplished through Jesus. For this reason we find the Father and the Son spoken of together in connection with salvation.—Tit 2:11-13; 3:4-6. Source: https://wol.jw.org/en/wol/d/r1/lp-e/1200003848

What Is God’s Way to Salvation? Watchtower 1960: As mankind’s source of salvation Jehovah God provided the perfect man, whose life could ransom the human race, by transferring the life force of his chief angelic Son in the heavens to the womb of a virgin. Because the child that was born did not receive its life through Adam’s line of descent but from God, it was perfect. Thus Jesus Christ became equal to Adam and able to ransom mankind by laying down his perfect human life. “Just as the Son of man came, not to be ministered to, but to minister and to give his soul [or life] a ransom in exchange for many.”—Matt. 20:28. Source: https://wol.jw.org/en/wol/d/r1/lp-e/1960161#h=14

(Emphasis mine)

EDIT: I have deleted the part of my answer that caused offense and would refer instead to the 22 October 1976 Awake article, ‘How Many Saviors Do You Have?’ and invite people to read the article in its entirety to get the Jehovah’s Witness perspective, part of which says this:

Salvation belongs to Jehovah,” declared the inspired psalmist. (Ps. 3:8) Through his prophet Isaiah, the Almighty stated: “I—I am Jehovah, and besides me there is no savior.”—Isa. 43:11. But it may be asked: ‘Is not Jesus Christ the Savior? So, then, are not Jehovah and Jesus the same, making our Savior but one, God?’ But what about Jesus Christ? He, too, cannot be spoken of as being a Savior besides Jehovah, that is, as a rival of his Father. The Scriptures clearly establish that Jesus’ role as Savior was assigned to him by his Father... Because salvation comes from Jehovah God through Jesus Christ, a “great crowd” (standing before the throne and in front of the Lamb) is depicted in the book of Revelation as making the following declaration: “Salvation we owe to our God, who is seated on the throne, and to the Lamb.” (Rev. 7:9, 10) Source: https://wol.jw.org/en/wol/d/r1/lp-e/101976768 Here are the relevant Bible verses from the New World Translation:

Psalm 130:8 NWT: “And he himself [Jehovah] will redeem Israel...”

Luke 2:11 NWT: “because there was born to you today a Savior, who is Christ the Lord”

2 Timothy 1:9-10 NWT: “This was given us in [connection with] Christ Jesus before times longlasting, but it has now been clearly evident through the manifestation of our Savior, Christ Jesus...”

Titus 1:3 NWT: “under command of our Savior, God.”

Jude 25 NWT: “To the only God our Savior through Jesus Christ our Lord, be glory, majesty, might and authority for all past eternity and now and into all eternity. Amen.”

Jehovah is identified as the principal Savior, but Jesus Christ is called “our Savior,” even though he performs the salvation as the agent of Jehovah. Jehovah is the Source of salvation, accomplished through Jesus. That is the official view of Jehovah’s Witnesses. I think that means they have only one Saviour.