confused about build size

Hello, after building my project, in the Editor.log I see, a list of Textures, Meshes, Animations etc, and it says:
Complete size 708 mb 100%

But in my in my Data folder it’s creating a 3GB resources.assets.resS file. Can someone please explain the discrepancy between these 2 files sizes? I (obviously) need to trim down my project size, but need to understand how things work first. thanks.

Also, in the Editor.log I see a lot of items that are taking up .1kb. Some of the items shown below show a size of 1.3mb when I view the texture I the Editor.

0.1 kb 0.0% Assets/Resources/GameMaterials/Textures/Concrete1/concrete_Height.png
0.1 kb 0.0% Assets/Resources/GameMaterials/Textures/Concrete1/concrete_Color.png
0.1 kb 0.0% Assets/Resources/GameMaterials/Textures/Cells1/Cells1_Normal.png
0.1 kb 0.0% Assets/Resources/GameMaterials/Textures/Cells1/Cells1_Height.png
0.1 kb 0.0% Assets/Resources/GameMaterials/Textures/Bricks3/Bricks3_Normal.png
0.1 kb 0.0% Assets/Resources/GameMaterials/Textures/Bricks3/Bricks3_Height.png

Also I see this .png file is takig up 5.3 MB of space:
5.3 mb 0.9% Assets/Resources/GameMaterials/Textures/Flower1/Flower1_Normal.png

But in the Editor, I’ve Set the Max Size to a small size and am using a compressed format.
The previous says this should be only 84kb

Also, by optimizing some things I was able to change this (from the editor.log)

Complete size 708 mb 100% (in build attempt 1)
to this:
Complete size 613.0 mb 100.0% (in build attempt 2)

But in the build, the resources.assets.resS file remains huge, and exactly the same size as it would in the earlier build: 3,111,284kb

Can anyone help me understand these issues? I’d greatly appreciate it. Thanks!