It's a challenge to get blurring right, for sure.
The wider the angle, the deeper the depth of field (DOF) will be. A 28mm lens will have a wide field of view (FOV) and everything in focus from a few feet to infinity. A longer lens, like a 400mm will have a small FOV and a narrower DOF.. perhaps just a few feet.
When you have a narrow DOF in a wide angle image, the message to the brain is one of close proximity.. in extreme cases, macro (pure macro is a 1:1 ratio, where the subject of the image is the same size in real life as the image of it, burned on film). Thus, an LFS screenshot with a wide FOV and a narrow DOF very often makes the vehicles look like radio controlled cars. Sometimes even smaller than that.
If you're going for realism by blurring the background/foreground, I recommend starting with a screenshot with a very narrow FOV.
Hope this helps