NB! It seems this console command is not compatible with CS2.
Command Profile

CL_OBSERVERCROSSHAIR

CS:GO

This is the console command that controls whether or not you have a crosshair when spectating/observing players.

Syntax
cl_observercrosshair [0 / 1]

Description

This is the console command that controls whether or not you have a crosshair when spectating/observing players.

Syntax And Arguments

cl_observercrosshair [0 / 1]
0 / 1 Set to 1 to enable having a crosshair when observing, and 0 to disable it.