There are typically 2 interpretations to daniel 8: 1.) it is about Antiochus Epiphanes or 2.) about a future endtimes antichrist. If interpretation #1 is correct, then the "many days from now" is around 350-400 years (time from Daniel to Antiochus). If interpretatation #2 is correct, then the "many days from now" is +2,500 years (time from daniel to future antichrist). Either way, whether the "many days from now" is 350-400 years or +2,500 years, daniel is told to seal up the vision because it's for the future.
Daniel 8:26 The vision of the evenings and the mornings that has been spoken is true. Now you must seal up the vision, for it concerns many days from now.”
However, when we come to Revelation, John is told NOT to seal up the prophecy because the time is near. Looking back at daniel 8, and in order to be consistent, if interpretation #1 is correct, then the "time is near" in revelation should be much less than 350-400 years. If however, interpretation #2 is correct, then it doesn't make much sense for the angel to tell John "the time is near" for +2,000 years (time from John to end times antichrist), while daniel is told "many days from now" for +2,500 years (time from Daniel to antichrist). This would be significantly inconsistent for the "near" and "distant" time frames given by the angel.
Revelation 22:10 Then he told me, “Do not seal up the words of prophecy in this book, because the time is near.
Daniel 8:26 The vision of the evenings and the mornings that has been spoken is true. Now you must seal up the vision, for it concerns many days from now.”
However, when we come to Revelation, John is told NOT to seal up the prophecy because the time is near. Looking back at daniel 8, and in order to be consistent, if interpretation #1 is correct, then the "time is near" in revelation should be much less than 350-400 years. If however, interpretation #2 is correct, then it doesn't make much sense for the angel to tell John "the time is near" for +2,000 years (time from John to end times antichrist), while daniel is told "many days from now" for +2,500 years (time from Daniel to antichrist). This would be significantly inconsistent for the "near" and "distant" time frames given by the angel.
Revelation 22:10 Then he told me, “Do not seal up the words of prophecy in this book, because the time is near.