QGIS Expression to label direction towards map center

I render a some bus lines maps using QGIS Map Composer, and i want to much large scale as possible, and i need to optimize label placement.

Cartographic placement settings

Label placement towards map center

Label placement settings

CASE 
WHEN  $x < x(  transform( @map_extent_center,'EPSG:3857','EPSG:4326') ) THEN 2 
ELSE 0
END

See real-life example at https://commons.wikimedia.org/wiki/File:Vidnoye_bus_map_2018-11-25_v1.svg