Another option is to host the comments in Github/Gitlab issues. There are several plugins that allow users to login using OAuth and post comments.

Gitalk is one of them: https://github.com/gitalk/gitalk/

Vssue supports both GitHub and GitLab, and allows users to edit and delete their comments: https://vssue.js.org/

And there is also Gitment: https://github.com/imsun/gitment