Explanation

Change the user name, not the email configuration.
Change a user's email address
You must be a global admin to complete these steps.
In the admin center, go to the Users > Active users page.
Select the user's name, and then on the Account tab select Manage username.
In the first box, type the first part of the new email address. If you added your own domain to Microsoft 365, choose the domain for the new email alias by using the drop-down list. Learn how to add a domain.
Select Save changes.
Reference:
https://docs.microsoft.com/en-us/microsoft-365/admin/add-users/change-a-user-name-and-email-address

Explanation
When configuring a duplicate detection rule in Power Apps with Microsoft Dataverse, to automatically delete duplicate records during a data import, you should enable the "During data import" option. This option allows the detection rule to automatically delete duplicates as they are imported into the system, without requiring user intervention.
References:
* https://docs.microsoft.com/en-us/power-platform/admin/create-duplicate-detection-rule
* https://docs.microsoft.com/en-us/power-platform/admin/data-integration-duplicate-detection

Explanation
Box 1: Solution system settings
For Power Apps in Settings > Customizations > Customize the System you can configure email and document management, activate or deactivate processes, and more.
Box 2: Environment variable
When should Environment variables be used?
Some examples include:
When an input parameter needs to change across environments and should not be hard-coded. For example, a URL that points to a different resource in development and production environments.
If you're building a solution where your customer is required to provide an input value.
Application setup pages.
Incorrect:
A connection reference is a solution component that contains information about a connector.
Reference:
https://docs.microsoft.com/en-us/powerapps/maker/model-driven-apps/advanced-navigation
https://powerapps.microsoft.com/en-us/blog/environment-variables-available-in-preview/

Explanation
Box 1: Assign records to a service account and add the team member doing the verification by using an access team.
When to use access teams
* The teams are dynamically formed and dissolved. This typically happens if the clear criteria for defining the teams, such as established territory, product, or volume aren't provided.
* The team members require different access rights on the records. You can share a record with several access teams, each team providing different access rights on the record. For example, one team is granted the Read access right on the account and another team, the Read, Write and Share access rights on the same account.
* A unique set of users requires access to a single record without having an ownership of the record.
Box 2: Assign records to the QV team when the service request is completed.
Issues: More employees than are required can access individual client information and continue to have access after a service request is completed.
Management has decided to create a new qualification verification (QV) role to help ensure that clients get the most accurate results. This role examines completed work to ensure that nothing is missed.
* When users go on vacation, all their outstanding Service Request records are assigned to a substitute employee. The substitute employees are unable to see all the qualifications related to their service requests.
Reference:
https://docs.microsoft.com/en-us/power-apps/developer/data-platform/use-access-teams-owner-teams-collaborate