Input validation is a technique that checks the user input for any errors, malicious data, or unexpected values before processing it by the application. Input validation can prevent many common web application attacks, such as:
SQL injection, which exploits a vulnerability in the application's database query to execute malicious SQL commands.
Cross-site scripting (XSS), which injects malicious JavaScript code into the application's web page to execute on the client-side browser.
Directory traversal, which accesses files or directories outside of the intended scope by manipulating the file path.
In this case, the security engineer should recommend input validation as the best mitigation technique, because it would:
Prevent the exfiltration of a company report by validating the file parameter in the URL and ensuring that it matches a predefined list of allowed files or formats.
Enhance the security of the web application by filtering out any malicious or invalid input from users or attackers.
Be more effective and efficient than other techniques, such as firewall, WAF (Web Application Firewall), or DLP (Data Loss Prevention), which may not be able to detect or block all types of web application attacks.

We recommend that you encrypt your virtual hard disks (VHDs) to help protect your boot volume and data volumes at rest in storage, along with your encryption keys and secrets.
Azure Disk Encryption helps you encrypt your Windows and Linux IaaS virtual machine disks.
Azure Disk Encryption uses the industry-standard BitLocker feature of Windows and the DM- Crypt feature of Linux to provide volume encryption for the OS and the data disks. The solution is integrated with Azure Key Vault to help you control and manage the disk-encryption keys and secrets in your key vault subscription. The solution also ensures that all data on the virtual machine disks are encrypted at rest in Azure Storage.

WPA3-Personal is a simple, secure solution for a small business with a single access point. It uses a new security protocol called Simultaneous Authentication of Equals (SAE), which replaces the Pre-Shared Key (PSK) exchange with a more secure way to do initial key exchange. SAE also provides forward secrecy, which means that even if the password is compromised, the attacker cannot decrypt past or future data.
WPA3-Personal also uses AES-128 in CCM mode as the minimum encryption algorithm, which is resistant to offline password attacks. WPA3-Personal requires low administrative overhead and supports a single SSID with no guest access. Verified References:
https://www.diffen.com/difference/WPA2_vs_WPA3
https://www.thewindowsclub.com/wpa3-personal-enterprise-wi-fi-encryption
https://www.teldat.com/blog/wpa3-wi-fi-network-security-wpa3-personal-wpa3-enterprise/

Conduct input sanitization - The only sure way to prevent SQL Injection attacks is input validation and parametrized queries including prepared statements. The application code should never use the input directly. The developer must sanitize all input, not only web form inputs such as login forms.
A WAF protects your web apps by filtering, monitoring, and blocking any malicious HTTP/S traffic traveling to the web application, and prevents any unauthorized data from leaving the app. It does this by adhering to a set of policies that help determine what traffic is malicious and what traffic is safe.