Changing default passwords is a critical first step after acquiring new devices. Default credentials are widely known and publicly documented, so changing them prevents unauthorized access using this information.
Reference:
CompTIA Security+ SY0-701 Official Study Guide, Domain 3.1: "Changing default passwords prevents attackers from exploiting publicly available device information." Exam Objectives 3.1: "Implement secure network architecture concepts."

Side loading refers to the process of installing applications on a device from outside the official app store, which can introduce security vulnerabilities by bypassing standard app validation processes.Reference: Security+ SY0-701 Course Content, Security+ SY0-601 Book.

/32 would cover all possible subnets, & their communicating devices within the IP range, & destination 0.0.0.0/0 would cover the gateway surface of your network.

Capacity planning is the process of determining the resources needed to meet the current and future demands of an organization. Capacity planning can help a company develop a business continuity strategy by estimating how many staff members would be required to sustain the business in the case of a disruption, such as a natural disaster, a cyberattack, or a pandemic.
Capacity planning can also help a company optimize the use of its resources, reduce costs, and improve performance.