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

NET_FAKELAG

CS:GO

This command will simulate lag (high latency/packet delay) for the specified amount of milliseconds.

Syntax
net_fakelag [Milliseconds]

Description

This command will simulate lag (high latency/packet delay) for the specified amount of milliseconds.

How To Use net_fakelag

  1. Enable the developer console in Counter-Strike settings.
  2. Open the console with the tilde key (~).
  3. Enter net_fakelag [Milliseconds], replacing bracketed arguments with the value you want, then press Enter.

This legacy command is not currently listed as compatible with Counter-Strike 2.

Syntax And Arguments

net_fakelag [Milliseconds]
Milliseconds The amount of milliseconds to fake lag for. 2000 = 2 seconds.