As I understand this article, Git Credential Manager Core is not the same with Git Credential Manager or Windows Credentials. After using this command
printf "host=github.com\nprotocol=https\nusername=ooker777\npassword=ghp_yourToken" | git credential-manager-core store
I'm able to push. Checking Windows Credentials I only see my GitHub password is stored in there, which will not work because GitHub requires it to be token. So it's clear that I'm not using wincred.
Yet git config --global credential.helper still shows that I'm using wincred. Why is that?
wincred was the legacy credential storage on Windows.
It has been replaced by GCM (Git Credential Manager), and after Git 2.38.1, is called manager (no longer "manager-core")
If you have upgraded Git for Windows, you can safely change your credential helper to manager.
# up to Git 2.38.1 on Windows
git config --global credential.helper manager-core
# Git 2.39+
git config --global credential.helper manager