Jesus didn't know the content of the scroll before taking it from the hand of God in Rev. 5. The book of Revelation begins this way:
Rev. 1:1 A revelation by Jesus Christ, which God gave him ...
... and here:
Rev. 5:2 And I saw a strong angel proclaiming with a loud voice: “Who is worthy to open the scroll and break its seals?” 3 But no one in heaven or on earth or underneath the earth was able to open the scroll or to look into it. 4 I gave way to a great deal of weeping because no one was found worthy to open the scroll or to look into it.
No one until Jesus went back to heavens ... So, it is practically saying that what Jesus showed John was the content of the scroll he received some time after ascending ...
Anyone who reads the book of Revelation realizes that it contains specific details about previous teachings but more prophecies for the future that have not been given before. It seems clear to me that this new information would have much more importance for the true Christian congregations in the time of the end, these days, a "time of the end" that would include not only the Jewish territory, as was the case of Jerusalem and its temple in 70, but an end of the entire human system of things that is separated from God and influenced by its spiritual rulers.
When John said:
Rev. 1:9 I John, your brother and a sharer with you in the tribulation and kingdom and endurance in association with Jesus, was on the island called Patʹmos for speaking about God and bearing witness concerning Jesus. 10 By inspiration I came to be in the Lord’s day (...)
... he meant he was watching visions corresponding to the future "Lord's Day". He was watching the future. That "Lord's Day" he was watching on visions, was the same Lord's Day Paul talked about in:
2 Thess. 2:1 However, brothers, concerning the presence of our Lord Jesus Christ and our being gathered together to him, we ask you 2 not to be quickly shaken from your reason nor to be alarmed either by an inspired statement or by a spoken message or by a letter appearing to be from us, to the effect that the day of [the Lord] is here.
3 Let no one lead you astray in any way, because it will not come unless the apostasy comes first and the man of lawlessness gets revealed, the son of destruction. 4 He stands in opposition and exalts himself above every so-called god or object of worship, so that he sits down in the temple of God, publicly showing himself to be a god. 5 Do you not remember that when I was still with you, I used to tell you these things?
So we could say that, for example, the war in heaven and the expulsion of Satan from that environment after Jesus was enthroned (Rev. 12), would be a future event to John, since it was a new revelation given by God to Jesus and by him to John through the angel.
