Did saints in the afterlife acquire an ability to hear prayer by moving to a different realm?

Advocates of prayer to saints claim that the saints in heaven have abilities that people on earth don't have that allow the hearing and answering of prayers. Passages like Revelation 6:9-11 are often brought up as evidence of the heavenly saints' knowledge of earthly events, for example. I've responded to that argument before. See this recent post that discusses some Biblical passages that refer to the heavenly saints' ignorance of some events on earth.

Another approach advocates of prayer to saints take is to try to explain the absence of the practice in the Old Testament by appealing to a supposed inability to hear prayer in a particular part of the afterlife, such as Sheol. The saints were moved to a different realm of the afterlife later in history, after Jesus' death, a change that allowed them to hear and answer prayers. That still wouldn't explain the absence of prayer to saints in the remainder of the Biblical record and the earliest extrabiblical Christian sources, the Old Testament prohibitions of attempting to contact the dead, the patristic opposition to prayer to saints, etc. But it would at least explain a large portion of the evidence against the practice.

Just as advocates of such prayer have to justify their belief that saints in heaven have a particular level of knowledge, they also have to justify any assertion they make about a change in realms in the afterlife and the supposed implications of that change related to prayer to saints. It's not enough to merely claim that the heavenly saints have a certain amount of knowledge or have moved to another realm in the afterlife and can hear and answer prayers as a result. Those claims have to be argued for, not just asserted.