I think there’s time in heaven, but that heaven is eternal. Here’s my case:
Premise 1: Time is change. That means if atoms or arms or whatever is one place and THEN goes to another place, time exists. Same with thoughts, prayers, etc.
Premise 2: Angels go places, say things. Saint’s pray for us. Saints hear our prayers.
Conclusion: Since angels and saints (and demons in hell) do things in order, then time exits in the still eternal realms called heaven and hell.
Of course there is time in heaven, because there are created souls in heaven and created souls exist in time.
Unlike an eternal Being, which has no beginning, created souls only began to exist when they were created. But since they were created to be immortal, they will never have an end or cease to exist. They become
everlasting from the time they were created, which means that they exist in a time without end, or in
unending time. But this does not mean that created souls are eternal just because they are immortal and have an everlasting existence. Because eternal existence (which belongs only to God) is the complete and simultaneous possession of existence (past, present and future) in an indivisible, enduring NOW. In an eternal being the past, the present and the future are simultaneously present in the NOW, but this is not the case with immortal souls. Immortal souls have a finite past behind them and an infinite future ahead of them. Their past and their future do not simultaneously exist in an indivisible “now.”
The duration of angelic beings is different. It is intermediate between time and eternity. Theologians call their kind of duration
aeveternity. To describe this kind of duration, I’d say that angels are, in a way, eternal with respect to their natures or substances, but temporal with respect to their acts or operations. I said “in a way” because their natures or substances have a beginning when they were created, whereas the only one truly Eternal Being, which is God, has no beginning at all. However, since angels were created as immutable substances, they also possess simultaneous existence in their aeveternal duration. This means that what we call “past” and “future” are also simultaneously present in their “now.” But that is with respect to their substances. Their acts and operations exist in time. They have past acts and future acts, past thoughts and future thoughts, which happen in some kind of discrete time, if they are not continuous.
Just my 2 cents.