Brand Portal and Assets Essentials

The features and look-feel will be same as you are managing the assets in both the platforms.

The difference comes in license, pricing, user base of these tools. Brand Portal is primarily used for collaboration with channel partners, distributors, external users with internal org users.

More info: https://experienceleague.adobe.com/docs/experience-manager-brand-portal/using/introduction/brand-portal.html?lang=en#introduction