I am trying to sign out of a Google account I have on Chrome, running on macOS.
I do not see a “sign out,” “log out,” or a “remove account” button anywhere in the account dropdown. I only can see a “sign out of all accounts” button, which I do not want to do—I want to sign out of a specific account and remove it. I have tried going to myaccount.google.com, but it doesn’t show anything relevant there. I have tried everything I could find in other answers, but it seems like none of them are up to date. Perhaps the ability to sign out of a single account has been removed?
“Perhaps the ability to sign out of a single account has been removed?”
I am afraid you are correct.
It has nothing to do with the kind of the operating system (Mac, Windows, Linux etc) you use.
It also has nothing to do with the browser you use (being Chrome, FireFox, Safari etc).
It is ALL about the browser you are logged into from.
As per the official Google site:
When you sign out of one account, you also sign out of all your accounts on that browser:
On your computer, go to a Google page, like http://www.google.com.
On the top right, select your profile image or initial.
On the menu, choose Sign out.
Your future behaviour as a workaround
Try logging in using a private/incognito window.
What a default account is
In many cases, your default account is the one you signed in with first. On mobile devices, your default account can vary depending on your device’s operating system and the apps you use.