Explanation
Formula field and Dynamic Forms should be created to meet the requirements because a formula field can be used to count the number of open opportunities over US$10,000 related to an account using a roll-up summary filter condition, and Dynamic Forms can be used to display or hide a component on an account page based on a visibility filter using the formula field value. References:
https://help.salesforce.com/s/articleView?id=sf.customize_functions_i_z.htm

Explanation
Debug Log is a tool that captures information about database operations, system processes, and errors that occur when executing a transaction or running a unit test. Debug Log can help troubleshoot issues related to triggers, workflows, validation rules, or other custom logic by showing the order of execution and the values of variables and expressions

Explanation
Modify All is the level of access that the sales user will have on the Account object after being assigned to a muting permission set that mutes Delete access on Account. Muting permissions are a way to reduce or remove access to objects or fields for users who are assigned to permission set groups. Muting permissions can only mute object-level permissions, such as Create, Read, Edit, Delete, View All, or Modify All, but not field-level permissions or other permissions. Muting permissions can only reduce or remove access that is granted by other permission sets or permission set groups within the same permission set group, but not by profiles or other sources of access. Therefore, in this case, the muting permission set will only mute the Delete access on Account that is granted by the permission set group, but not the Modify All access that is also granted by the permission set group.

Explanation
Debugging a flow allows administrators to test how a flow behaves before activating it or making changes to it. Debugging a flow runs it in real time using test data provided by the administrator or default values from the flow. However, debugging a flow also performs any actions defined in the flow, such as creating, updating, or deleting records. Therefore, if a flow has a delete element that deletes a record based on certain criteria, debugging the flow will delete the test record even if the flow is inactive. References:
https://help.salesforce.com/s/articleView?id=sf.flow_debug.htm&type=5

Explanation
The Show Unique Count option on the account name column will create a report showing all open opportunities and the total number of accounts represented. This option will count each account only once, even if it has multiple opportunities. The report can be grouped by account name or any other field to show more details. References:
https://help.salesforce.com/s/articleView?id=sf.reports_builder_unique_count.htm&type=5