The problem with saying "the biblical basis for PSA is..." is that none of the passages provided actually speak of PSA.
A Mormon could take those verses, apply them to his faith, and say "there biblical basis for Mormonosm is...".
This is the problem with all these unbiblical theologies. They start with a theory and then look to the Bible for support.
We need to start with the Bible and first simply believe God's words.
‘And the LORD has laid on Him the iniquity of us all’ . ‘Who Himself bore our sins in His own body on the tree’ ‘The chastisement for our peace was upon Him, and by His stripes we are healed’. “For even the Son of Man did not come to be served but to serve, and to give His life a ransom for many’. “For You were slain, and have redeemed us to God by Your blood out of every tribe and tongue and nation and people”.“Behold, the Lamb of God who takes away the sin of the world”. ‘He was wounded for our transgressions, He was bruised for our iniquities’. “Therefore let it be known to you, brethren, that through this Man is preached to you the forgiveness of sins; and by Him everyone who believes is justified from all things from which you could not be justified by the law of Moses”. ‘Christ has redeemed us from the curse of the law, having become a curse for us (for it is written, ‘Cursed is everyone who hangs on a tree)’.
I believe the above. Many of us do, even some who advocate PSA believe those passages to an extent and in their own way.
The difference is PSA has to add "now let me tell you what that "really" means when "properly" understood.
The obvious question is...what if those words mean exactly what they say?