The Eternal God is before, through and beyond Time (which He created for our sake). What will take place beyond the return of Jesus Christ? We do know that for those who rise to meet the Lord, Time will then cease to exist. Paul the Apostle wrote that at the end of Christ’s reign, when all things will have been put “under his feet” — his dominion — Jesus will deliver the kingdom to God the Father, and the Son himself will then be subject unto Him, so that God may be “all in all” (1 Corinthians 15:24, 28).
What does “all in all” mean? Who knows? It’s best that for now we occupy ourselves with whatever we are able to do in the Lord’s service. As to the rest, we will have to wait until we are forever with the Father and the Son.
Our brains are wired for things that pertain to time, not things beyond it where different laws, i.e. heavenly ones, apply. Until then we have time to prepare ourselves through obedience to Christ, and do well to make the most with whatever time is left us. There’s no Time in Eternity but there is in this life. We’ll not need clocks then but for now Time is still ticking!
Meantime, like King David, we would do well to “wean” ourselves from things beyond our ability to grasp (Psalm 131:1-3). We know more than enough to keep us busy in the foreseeable future. Albert Einstein said: “Imagination is more important than knowledge.” Maybe so, but revelation is much more important than imagination.
What we don’t know at present, we will know soon. Sooner than we think. The answers to all our questions will be made known to us the moment our mortal bodies become immortal and our minds become the mind of Christ and all our questions will be replaced by What’s Not to Know?