THIS FEATURE HAS BEEN IMPLEMENTED INTO VH3.11.3 (vh mod jar: the_vault-1.18.2-3.11.0.2611.jar), therefore I am archiving it and removing it from curseforge

This server-side mod pauses timer when you enter vault and resumes it after you move certain distance.
Default distance is 18, which is enough to allow free movement in the first room. (this is 2D distance, so you can be at any height)
This allows you to let the chunks load when you are in the first room without losing vault time.