Google Chrome incognito (private/anonymous browsing) not available in Google Workspace (GSuite) account

Recently, incognito mode disappeared in Chrome while signed-in as Google Workspace account (signed-in as regular gmail account has been working just fine).

So I did an obvious check on policies (chrome://policy/), everything looked just fine:

So I got quite confused and had started to Google around and came to this (https://chromeenterprise.google/policies/?policy=IncognitoModeAvailability):

If anybody from Google is reading this, please... why on Earth an attribute called "...Availability" set on "1" means DISABLED?! I consider it highly non-standard and counter-intuitive.

Anyways, we've browsed through our GPO in AD and found nothing.

So the Google Admin... And indeed, there is a manual change which has to be made (see below in the answer).

Here is the solution, go to https://admin.google.com/ac/chrome/settings/user and change manually "Incognito mode" to Allow.