I only see those organizations which are attached to the AAD.
According to your description, this should be an expected behavior. Since you organization is detached from the AAD. It will definitely not shown in the same list of those organizations still in AAD.
In other words, you are using the account which backed in AAD to login Azure DevOps.
To see this organization, you need to use personal account (Even it's totally the same name compared with work account) to login that Azure DevOps Organization.
but the option is not there in the dropdown in the profile section. Yes, there is no such option setting. You could take a look at our official doc here:
Why can't I sign in after I select "personal Microsoft account" or
"work or school account"?
Although both identities use the same sign-in address, they're
separate: they have different profiles, security settings, and
permissions. Sign out completely from Azure DevOps by completing the
following steps. Closing your browser might not sign you out
completely. Sign in again and select your other identity:
- Close all browsers, including browsers that aren't running Azure
DevOps.
- Open a private or incognito browsing session.
- Go to this URL: https://aka.ms/vssignout.
You see a message that says, "Sign out in progress." After you sign
out, you're redirected to the Azure DevOps @dev.azure.microsoft.com
webpage.
If the sign-out page takes more than a minute to sign you out, close
the browser and continue.
- Sign in to Azure DevOps again. Select your other identity.
Suggest you to use a InPrivate mode browser to login, then use your Microsoft Account to authenticate, also select personal account if you need to choose between a "work or school account" and my "personal account".