The nearby map component on the promotion records page allows a user to see which stores are running a promotion within their vicinity. This solution meets the requirement and also involves the least amount of custom development, as it is a standard feature of Consumer Goods Cloud. Verified Reference: [Salesforce Consumer Goods Cloud Implementation Guide], page 32.

To allow Sales Managers to create and assign delivery tasks to deliver, the following setup steps should be configured:
Create an action plan template with a Delivery Task and assign it to a Visit. A Delivery Task is a type of action plan task that allows a field rep to deliver products to a retail store. A Visit is a scheduled or unscheduled interaction between a field rep and a retail store.
Assign the Lightning Direct store Delivery permissions set to the user. This permissions set grants access to the delivery task functionality and related objects, such as product transfers and shipments.
Assign the Action Plans permission set to the Sales Manager. This permissions set grants access to the action plan functionality and related objects, such as action plan templates, action plan tasks, and assessments. Verified Reference: [Salesforce Consumer Goods Cloud Implementation Guide], page 28-29.

Two explanations for why no surveys are available when field reps try to complete a visit survey on their mobile devices are:
The Salesforce admin has not created and activated a Salesforce survey. A Salesforce survey is a questionnaire that can be sent to customers or contacts to collect feedback. The admin needs to create and activate a survey before it can be used in an in-store survey task.
A related survey invitation has not been generated. A survey invitation is an object that represents an invitation to take a survey. A survey invitation needs to be generated and associated with the visit, the retail store, or the store primary contact before it can be displayed in an in-store survey task. Verified Reference: [Salesforce Consumer Goods Cloud Implementation Guide], page 27.