An on-going process
Being born anew is in the present progressive tense. It is not a one time occurrence, but rather being born by stages of glory into becoming like Him.
The Greek verb for must ("δει") as in "you must be born anew" (John 3:7) is in the present tense indicative mood. Denoting a continued need now, and going forward.
All dimensions of the old-man nature must be eclipsed by the working of the flaming swords of the Lord swirling in every direction. The way back into the Tree of Life is guarded by Cherubim preventing fallen flesh from entrance.
The purpose of the cross is to do away with you, blessed riddance. -A.W. Tozer