How to delete non-existant work/school account from windows 10 local account

Select "Access work or school" instead of "Email & accounts" Then you can select the work account and you get the Disconnect button. Disconnect Work Account - windows 10

My Windows version: Windows 10, 1909.

In Windows' "Your info" select "Sign in with a local account instead" and change your account to a local account. You will have to enter a password for the local account.

This will log you out and then back in using the new password.

Return to "Your Info" and disconnect all the accounts you want to get rid of on either the "Access work or school" page or the "Your Info" page.

When done, return to "Your Info" and sign in with your Microsoft account again.