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

M_MOUSEACCEL1

CS:GO

This console command sets the mouse acceleration value for its initial threshold, up to 2x movement speed.

Syntax
m_mouseaccel1 [Value]

Description

This console command sets the mouse acceleration value for its initial threshold, up to 2x movement speed.

Syntax And Arguments

m_mouseaccel1 [Value]
Value The value you want to set mouse acceleration to for the initial speed threshold (up to 2x). The default value for this command is 0.