I would like to take a closer look at the scriptures you are thinking of...please quote them for me.
Certainly.
The following verses demonstrate that the sacrifice of Jesus on the Cross unconditionally redeemed ALL mankind:
“he is the expiation of our sins, and
NOT FOR OURS ONLY but also for the sins of the
WHOLE WORLD” (1John 2:2)
“God our Savior who desires ALL men to be saved … the man Jesus Christ who gave himself as a ransom for ALL” (1Tim 2:3-6)
“one man’s act of righteousness leads to acquittal and life for ALL MEN” (Romans 5:18)
“Behold the Lamb of God, who takes away the sin of the WORLD” (John 1:29)
“For God sent the Son in the world, not to condemn the world, but that THE WORLD might be saved through Him” (John 3:17)
“The death He died, He died to sin, once for ALL” (Romans 6:10)
“He has appeared once for ALL at the end of the age to put away sin by the sacrifice of himself” (Heb 9:26).
But although all mankind (even atheists) have been redeemed by the Cross, the benefits of redemption can only be “received by faith” (Romans 3:21-26). So to those without faith, the redemption is of no benefit at all - all mankind has been redeemed by the Cross, but not all mankind will be saved and make it to Heaven.