Indoor modeling - everything appears smaller (narrower) than it should be

First of all, I need to note that there is problem is not related to importing and scaling problems: I am following real metrics and made sure that Unity follows it on a 1:1 scale;

I made sure the sizes are correct by creating a wall at eye level of 1m and 75cm, the same as the eye level of the first person character class in Unity. Now when I make any object, for example a bed and place it near the camera it looks way smaller than it should be (?).

Does anyone know what this is caused by? I’ve got a feeling it is not a Unity problem but more generally a problem always related to 3D video game development. Here is a question made by somebody else which explains exactly the problem: Reddit - Dive into anything But nobody really gave an appropriate answer (changing POV feels way too weird)

To better understand what I mean here is a model I recreated in Sketchup of my room. I stayed faithful to the real sizes of the room, as it can be noticed from the height of the glass window door. But the problem are the X and Z axes. To make the room look the real size (in the screenshot), I had to stretch the tatami (flooring) size by a factor of 1.6. I could test this by standing on a single tatami mat both in reality and in-game. By looking down at the mat it would look much much smaller than it is in real world. And again, I am sure it is not a scaling problem as the Y axis is perfectly aligned.

The proble in the posted image is simple …

The grass texture is tremendously too large. Change the texture scale on the grass to 50x or 100x smaller.