The floor area does not change, but our perception of open floor, walkways, light and long sightlines does. A rearrangement can therefore have more impact than new decor.
Clear walkways feel larger
When there is an obvious route from the entrance, the room feels less crowded. Furniture blocking circulation makes the space feel smaller.
Visible floor matters
Furniture on legs and fewer small objects reveal more continuous floor area, which the brain interprets as openness.
Do not block natural light
Tall furniture near windows can reduce daylight. Brighter rooms are often perceived as more spacious.
Fewer, stronger groupings reduce visual clutter
A few well-grouped pieces can feel calmer than many small objects around the room. Visual clutter makes a space feel tighter.
Bottom line
Keep the solution simple: start with the most likely cause, change one factor at a time, and observe the result. That makes it much easier to identify what actually works in your situation.