There is no such thing as "provisional atonement"! Either Jesus atoned for his people on the cross, or he did not (he did!). The benefits of that accomplished atonement are fully applied when we believe in Jesus, but the atonement was accomplished on the cross.
Scripture says there is atonement provided for everyone.
John 1:29
The next day John saw Jesus coming toward him and said, “Look, the Lamb of God, who takes away
the sin of the world!
Hebrews 2:9
But we do see Jesus, who was made lower than the angels for a little while, now crowned with glory and honor because he suffered death, so that by the grace of God he might
taste death for everyone.
Titus 2:11
For the grace of God has appeared, bringing salvation
to all men,
Titus 3:4
But when the kindness and the
love of mankind of God our Savior appeared
John 3:16
For God so
loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life.
1 Timothy 2:4
Who will have
all men to be saved, and to come unto the knowledge of the truth.
2 Peter 3:9
The Lord does not delay his promise, as some regard “delay,” but he is patient with you, not wishing that any should perish but that
all should come to repentance.
1 John 2:2
He is the atoning sacrifice for our sins, and not only for ours but also for the sins of
the whole world.
2 Corinthians 5:14
For Christ’s love compels us, because we are convinced that one died for all, and therefore
all died.
hope this helps !!!