As is, two immediate thoughts come to mind…the sink should be in a cabinet incorporated in the cabinetry design. A tall shallow closet(s) on wall opposite door could provide more storage for vacuum and more. But the best plan will maximize storage/functionality for your family. How many people/children will be accommodated in this space? Young or old? If young kids, accessibility/flexibility are key. Are you in a climate with snow or a lot of rain? Need ventilation for wet clothes/footwear/gear. What needs to be stored there? How many shoes/boots? All of these questions will inform how the space is designed to maximize its usage.

This is such a good stage to rethink the mudroom, especially since you are adjusting the garage space.

Mudrooms always seem simple until you start listing everything that needs to live there.

Do you picture this mostly handling coats and shoes or more of a utility space with the sink being used regularly?

Can enlarge room/storage closet/counter, add garage landing, etc to this concept as garage space allows.

Oh my goodness. A long time ago I had considered moving our stair location to make it more efficient path of travel. I appreciate this a lot!