I have added the following articles for you to compare DDOS Tiers
https://www.linkedin.com/pulse/azure-ddos-protection-understanding-basic-standard-tiers-butola/
https://learn.microsoft.com/en-us/azure/ddos-protection/ddos-pricing-guide
Free Azure DDoS Protection is enabled by default for all resources within an Azure virtual network and is enabled at no additional cost. Free DDoS Protection defends against common network-level attacks with real-time traffic monitoring and mitigation. Free DDoS Protection s goal is to keep network infrastructure resources available and responsive during attacks.
If you haven't explicitly enabled any Azure DDoS Protection Tier, your public IP address may appear as "Not Protected." The DDoS Protection Tiers add more mitigation capabilities than the Basic service tier, such as tuning for Azure Virtual Network resources, cost protection, and logging.
Please keep in mind that DDoS Protection Tiers are paid services that are billed based on the number of protected resources, protection plan, and outbound data transfer.