if as it says "God is saviour of all men but especially of believers! then how are unbelievers saved?

John 3:18.

Those who believe are not judged in the sense of being found guilty and sentenced. All are guilty. All have sinned and fallen short of the glory of God. For the believer, the debt has been paid by Jesus at Calvary. There is therefore no condemnation. For those who are in Christ Jesus - Romans 8:1

Correct.

And that answers your original question.

The blessing is the acceptance of the gospel of Jesus Christ as preached to all the nations, as commanded by Jesus himself to his disciples.

Paul uses childbearing as a figure of speech known as a synecdoche. A synecdoche is a figure in which the part stands for the whole. Childbearing is a part of a larger whole, which is the woman’s wider role to care for the home. This is the same role Paul describes in Titus 2:4–5: “Young women [are] to love their husbands and children, to be self-controlled, pure, working at home, kind, and submissive to their own husbands, that the word of God may not be reviled.”

So, in both 1 Timothy 2 and Titus 2, Paul declares that wives have a God-ordained role to play in caring for children and the home. This is not claiming that a woman must have children in order to be saved. It is not even teaching that a woman must be married to be saved. But for those women who are married, God assigns a special responsibility to care for the home.

A wife’s fulfillment of this role will be one of the evidences of perseverance in the faith. Salvation is future in this verse: “She will be saved.” Thus it is not entry into salvation that is in view but the future consummation of salvation. Women who embrace their God-ordained role while continuing in the Christian virtues of “faith and love and holiness, with self-control” will find themselves saved on the last day.

Those from all the nations who haven’t accepted Jesus as Lord and Saviour.

Those who believe come out from the nations and into the kingdom of God. They are redeeemed by Christ. Those who remain unsaved in the nations are not redeemed, and therefore must face judgement for the sins they have committed.