Deprecated plugins tend to continue operating, though that specific plugin warns in its documentation that it was an experiment and is not considered ready for production.
Pipeline is a good recommendation to replace the multiple SCM's plugin with something more reliable, more consistent, and better supported. You say that you prefer to use dashboard to configure some steps. Pipeline can be configured from the Jenkins user interface though it is generally considered much better to use a git repository to track the pipeline definition.
You could create a git repository with the sole purpose of defining the checkout commands for your multiple SCM use case. A single Jenkins pipeline can checkout from multiple SCM's