The object scale is unapplied and also non-uniform. Ctrl+A -> scale to apply. http://pasteall.org/pic/show.php?id=72366
A simple box doesn’t need subdivision surfaces. You’re showing a 1/4 of a box; if the purpose is to use mirror modifier for the whole one, you don’t fill it with faces on the mirror planes as that creates mesh errors when mirror merges them.
Topology requirements come from the forms and design, pipeline stages, and the targeted end use (still, animation, game engine, 3d printing, other (what?)). The only requirement you mention is to have it support subdivision surfaces, which can be done in two ways: edge creasing or perimeter loops.
If you select everything in a cube, shift+e and drag the mouse to have crease value of 1, subdivision surface won’t deform the cube. Alternatively if you add a bevel modifier to a cube, 2 cuts, profile 1, it adds perimeter loops on every side which concentrate subdivisions near the corners. But if it’s a simple box, one doesn’t subdivision surfaces to refine rounded forms because there aren’t many of those, could instead use bevel to add the rounded edges with much less geometry.