But, like it says in 1 Corinthians, " . . . these three remain, Faith, Hope, and Love."
And those are what will fit us for eternity with the Lord Jesus Christ. That eternity in perfect love will be more than merely bearable. Every moment will be like His mercy, renewed every day.
The Song of Solomon has a verse which reads,
"He brought me to the banqueting house, and his banner over me was love." (Song of Solomon 2:4)
Try reading the Song of Solomon in the light of future glory with Jesus. It sounds good to me.
The love of Jesus, Who is preparing a place for us so that where He is we may be also, will not grow tiresome.
As far as having any purposeful activity. Mark Twain mocked at the boring idea of sitting on a cloud strumming a harp. Well, Romans chapter one tells us that what God has created tells us about who He is. What He has created is pretty amazing, and it may well take more than an eternity to plumb the depths of the new earth and the new heavens, which will probably be even more amazing, and it will take more than eternity to get to know Him - which will be the most amazing thing of all, well deserving of an eternity. And we, created in His image, will like Him, our Creator, delight in some manner of creativity
I wonder if, when “forever after” begins, the Lord will still delight in creativity, or if He will be done with that.
This is in Captain Stormfield's Visit to Heaven, a very extensive and thought-provoking discourse on the idea of eternal hevenly life, though certainly in a light-hearted and humorous vein.