Clone by Bounds (Editor & Runtime)

The plugin allows you to duplicate actors by their bounding box size and place them flush against each other. This makes it easier to place walls, floors, and other objects when their dimensions are not multiples of 5 or 1 centimeter, for example, if an object’s length is 25.6.

Settings and quick action button:

FAB: Clone by Bounds (Editor & Runtime) | Fab

Doc: Here