God is, was and always will be the same. We experience time, which He takes part in with us in The Form of Flesh.
The triune relations apart from material creation experienced thinking, acting, feeling, relationship, fellowship, love, etc. These things all presume sequence, succession, duration (i.e. time). There is a before and after creation. Eternity is not timelessness/simultaneity/eternal now (pagan philosophy), but endless duration/time.
A timeless being could not experience time, creation would be co-eternal with Him, etc. God is the same in some ways, but not other ways. The incarnation is a new change in the being of God. He had eternity past to experience triune relations before the change of relationships with created beings/reality.
Your ideas are simplistic, not defensible nor thought out.
Rev. 1:4 uses tensed expressions about God. Like other personal beings, He has a past, present, future. This is evidenced on every single page of Scripture that shows duration in the divine being without hints that it is figurative vs literal revelation.