In Heaven, aren’t we joined with Christ perfectly?
Aren’t we told that even on earth we can 'make a lives a prayer"?
I would think that in being joined with Christ and having the ability to know, love, and serve God perfectly, loving our neighbor as ourselves perfectly, being free from all want and all fear, free of all evil, completely filled with the Holy Spirit, etc., that our lives then would indeed be a perfect prayer. And each person will worship slightly differently, because we are different people.
We may (or may not) use ‘earthly things’. Some people are excellent pianists, for example, and in their playing they are, in effect, praying, offering worship to God who gave them the gift of music. So these people might be praying in music, but the music might be something ‘like’ a piano in some ways, and in others, completely different and perfect.
Same with people who did artistic things.
With people who found beauty in nature.
People who found themselves worshiping God most when they were serving others.
And in addition, people who may have never found themselves inclined to one of the above --the tone deaf person, perhaps–may find themselves drawn to music and ‘praying’ as they never could before.
The tenderfoot or recluse who never willingly set foot ‘outside’ might be called to see beauty and ‘pray’ in that way.
What a joy it will be to, indeed, ‘pray unceasingly’.