To be notified of any abnormal subscriber behavior with its 'Weekly Deal email, you should use Einstein Messaging Insights. This feature provides notification badges to alert you of any performance issues or opportunities with your email campaigns. You can see how your emails are performing compared to your historical averages and benchmarks, and get recommendations on how to improve your results.

Leveraging Multilingual Content Blocks is the best option for NTO to create and send localized content at scale. Multilingual Content Blocks allow you to create a single content block that can display different versions of text based on the subscriber's preferred language. You can use a spreadsheet or a data extension to store the translations and then map them to the content block. This way, you can avoid creating multiple templates or emails for each language. Leveraging templates with AMPscript or Enhanced Dynamic Content would require more coding and development skills.

Frequency split is a journey builder activity that splits contacts based on how often they have received messages from the account. It can be used to focus marketing efforts on subscribers who are least likely to unsubscribe by sending them fewer or more relevant messages. Path optimizer and scoring split are not related to frequency.

Engagement Split is the Journey Builder activity that NTO should use. Engagement Split is an activity that allows you to split contacts based on how they interacted with a previous email send, such as opened, clicked, or converted. You can use this activity to include specific content for your most engaged customers and different content for your least engaged customers. Frequency Split is an activity that allows you to split contacts based on how often they have received messages from your account. Scoring Split is an activity that allows you to split contacts based on their Einstein Engagement Score.

A collection is a group of related reports that can be created in Datorama to provide customized insights and analysis. A collection can contain reports from different data sources and channels, as well as filters, segments, and calculations. A collection can be shared with other users or embedded in other applications.