Hello,
Generally for the Variable Products at WooCommerce end it shows the Price Range but if the Price under the Price Range isn’t correctly appearing on your Site even with the Storefront Theme too then it means that it is not a Theme specific issue, it is an issue either at some third party Plugin conflict or at WooCommerce level on your Site.
So, please once try deactivating all the third party Plugins on your Site, remaining the Theme required ones activated. If the issue gets resolved, then reactivate them one by one to see which Plugin is causing the issue. If this doesn’t work for you then try contacting the WooCommerce Support in this regard they can guide you better with this.
Best Regards