I don't see "many" as a contradiction to "all".Is there a contradiction here ? Jesus said He gave himself a ransom for many Mark 10:45
For even the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many.
And His faithful apostle wrote that Jesus gave His life a ransom for all 1 Tim 2:6
6 Who gave himself a ransom for all, to be testified in due time.
Now here is a writing that I believe reconciles what appears to be a contradiction, and will go on to confirm limited atonement: Craig A. Thurman
Certainly "all" are "many".