I'm using a localized (Polish) version of Windows. That means typing 'Credential Manager' in search doesn't turn up anything relevant. I can't spot anything that would match the name in my language in the Windows Settings. All the articles either say 'type in search' or 'find in settings' but without knowing what translation (...certainly not direct because there's nothing matching) Microsoft used I can't guess where it is. Could you provide e.g. a screenshot, detailed guide of which UI elements to click (not depending on English names) or a command - or just the Polish translation which Microsoft happened to apply - to launch it?
(I mistyped my password in TortoiseGit and it remembered it that way and now fails to log into the repository due to having stored invalid credentials and I can't remove them.)
cmdkey /list
to show the certs and their identifiers, thencmdkey /delete:git:http://gitlab....
to delete it.