You hit on a lot of points I'd been thinking about John.
Fully accomplished outside of time, still being walked out within time.
The Lamb was slain from the foundation "outside time", 2000 years ago within time.
Salvation accomplished from the foundation outside time, only when the Holy Spirit draws each one and God provides faith to believe unto salvation within time.
When God visited me, it wasn't to tell me I was saved. It was to tell me I needed the Savior. He then gave me faith to believe in Him already slain and risen, and the strength to call on Him at that time He had so graciously appointed for me (nothing of myself).
It's a mystery. Thank God for His mercy.