Thank you for reaching out.
As documented here, you can run the commands below to verify that the DDoS protection plan is configured correctly. You can refer to this document for example outputs for the commands below.
Get-AzDdosProtectionPlan -ResourceGroupName MyResourceGroup -Name MyDdosProtectionPlan
Get-AzVirtualNetwork -Name MyVnet -ResourceGroupName MyResourceGroup
In the question you have mentioned about activity logs (Not sure if you meant Diagnostic Logs). As documented here the Azure Monitor activity log is a platform log in Azure that provides insight into subscription-level events. The activity log includes information like when a resource is modified or a virtual machine is started etc.
If not already done so, you can enable diagnostic logging for your DDOS plan as documented here and view and telemetry as discussed here.
You can also run a simulated DDOS attack to test how your services will respond in case of an attack.
Hope this helps! Please let me know if you have any additional questions. Thank you!
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.