Half/quarter of the native resolution on a MacBook with Retina display

I have a MacBook Pro notebook with native resolution of 2560x1600 which makes all my desktop details unreadable. I tried increasing DPI, but icons remain small, so I decided to decrease display resolution. I thought that resolution of 1280x800 would work the best, as 4 pixels of the native resolution would become one pixel in the lower resolution. But 1280x800 is not available to set:

$ xrandr -q
Screen 0: minimum 320 x 200, current 2560 x 2538, maximum 32767 x 32767
eDP1 connected 1440x900+0+1638 (normal left inverted right x axis y axis) 286mm x 179mm
   2560x1600      60.0 +
   2048x1536      60.0  
   1920x1440      60.0  
   1856x1392      60.0  
   1792x1344      60.0  
   1920x1200      60.0  
   1920x1080      59.9  
   1600x1200      60.0  
   1680x1050      60.0     59.9  
   1600x1024      60.2  
   1400x1050      60.0  
   1280x1024      60.0  
   1440x900       59.9* 
   1280x960       60.0  
   1360x768       59.8     60.0  
   1152x864       60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
DP1 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
   2560x1440      60.0*+
   1280x720       59.9  

So I set resolution of 1440x900 and the desktop is blurry.

I tried setting the native resolution with xrandr --output eDP1 --scale .5x.5 but the effect s not any better.

How to set 1280x800 resolution which is 1/4 size of the native resolution of 2560x1600 to make my screen look better?

UPDATE:

It's strange: when I boot to MacOS and try changing retina display resolution to scaled it also offers 1440x900, but the resulting picture is very good.