Explanation:

Display the time and process information of the device, as well as CPU, memory, and disk usage data. = show sdwan system status1 Validate the configured zone-based firewall. = show policy-firewall config1 Display information about application-aware routing policy matched packet counts on the Cisco IOS XE SD-WAN devices. = show sdwan policy app-route-policy-filter1 View the security information that is configured for IPsec tunnel connections. = show sdwan security-info The commands used to identify issues on a Cisco IOS XE SD-WAN device are as follows1:
show sdwan system status: This command is used to display the time and process information of the device, as well as CPU, memory, and disk usage data1.
show policy-firewall config: This command is used to validate the configured zone-based firewall1.
show sdwan policy app-route-policy-filter: This command is used to display information about application-aware routing policy matched packet counts on the Cisco IOS XE SD-WAN devices1.
show sdwan security-info: This command is used to view the security information that is configured for IPsec tunnel connections1.
References :=
Cisco IOS XE Catalyst SD-WAN Qualified Command Reference
Cisco Catalyst SD-WAN Command Reference
Cisco Catalyst SD-WAN Systems and Interfaces Configuration Guide, Cisco IOS XE SD-WAN Tunnel Interface Commands - Cisco

An identity mismatch occurs when the local and remote identities configured on the IPsec peers do not match.
This can prevent the establishment of an IPsec tunnel or cause traffic to be dropped by the IPsec policy. In this case, the network engineer should verify that the local and remote identities configured on the Cisco WAN edge router and the AWS endpoint match the values expected by each peer. The identities can be an IP address, a fully qualified domain name (FQDN), or a distinguished name (DN). The identities are exchanged during the IKE phase 1 negotiation and are used to authenticate the peers. If the identities do not match, the peers will reject the IKE proposal and the IPsec tunnel will not be established or will be torn down.
References :=
Configure IOS-XE Site-to-Site VPN Connection to Amazon Web Services, Topic: Troubleshooting Designing and Implementing Cloud Connectivity (ENCC) v1.0, Module 3: Implementing Cloud Connectivity, Lesson 2: Implementing Cisco SD-WAN Cloud OnRamp for IaaS, Topic:
Troubleshooting Cisco SD-WAN Cloud OnRamp for IaaS
Cisco IOS Security Configuration Guide, Release 15M&T, Chapter: Configuring IPsec Network Security, Topic: Configuring IPsec Identity and Peer Addressing

The connectivity model that meets the requirements of high availability, redundancy, and low latency for the company's business applications is ExpressRoute with private peering using SDCI.
ExpressRoute is a service that provides a dedicated, private, and high-bandwidth connection between the customer's on-premises network and Microsoft Azure cloud network1.
Private peering is a type of ExpressRoute circuit that allows the customer to access Azure services that are hosted in a virtual network, such as virtual machines, storage, and databases2.
SDCI (Secure Data Center Interconnect) is a Cisco solution that enables secure and scalable connectivity between multiple data centers and cloud providers, using technologies such as MPLS, IPsec, and SD-WAN3.
By using ExpressRoute with private peering and SDCI, the company can achieve the following benefits:
High availability: ExpressRoute circuits are redundant and resilient, and can be configured with multiple service providers and locations for failover and load balancing1. SDCI also provides high availability by using dynamic routing protocols and encryption mechanisms to ensure optimal and secure path selection3.
Redundancy: ExpressRoute circuits can be paired together to form a redundant connection between the customer's network and Azure4. SDCI also supports redundancy by allowing multiple connections between data centers and cloud providers, using different transport technologies and service levels3.
Low latency: ExpressRoute circuits offer lower latency than public internet connections, as they bypass the congestion and variability of the internet1. SDCI also reduces latency by using MPLS and SD-WAN to optimize the performance and quality of service for the traffic between data centers and cloud providers3.
References:
What is Azure ExpressRoute?
Azure ExpressRoute peering
Cisco Secure Data Center Interconnect
ExpressRoute circuit and routing domain

To enable the OMP advertisement of BGP routes for a specific VRF instance on a Cisco IOS XE SD-WAN device, the engineer must first configure the global address-family ipv4 and then enable bgp advertisement under the vrf definition. This will allow the device to advertise the BGP routes learned from the cloud provider to the OMP control plane, which will then distribute them to the other SD-WAN devices in the overlay network1 References := 1: Designing and Implementing Cloud Connectivity (ENCC) v1.0, Module 3: Implementing Cloud Connectivity, Lesson 3: Configuring IPsec VPN from Cisco IOS XE to AWS, Topic: Configuring BGP on the Cisco IOS XE Device, Page 3-24.

A fully meshed topology with SD-WAN technology, using dynamic routing and BGP as the routing protocol, meets the requirements of the company because it provides the following benefits:
It allows direct and secure connectivity between any two branch offices, without the need for a central hub or intermediary devices12. This reduces the latency and improves the performance of the critical business applications.
It leverages SD-WAN technology to optimize the traffic flow and application quality of service (QoS) across the WAN13. SD-WAN can dynamically select the best path for each application based on the network conditions and policies13. SD-WAN can also provide redundancy, security, and visibility for the WAN13.
It uses dynamic routing and BGP as the routing protocol to exchange routing information and establish connectivity between the branch offices14. BGP is a scalable and flexible protocol that can support multiple address families, such as IPv4 and IPv6, and multiple routing policies, such as local preference and route filtering14. BGP can also enable seamless integration with the cloud service providers (CSPs) and internet service providers (ISPs)14.
References :=
1: Designing and Implementing Cloud Connectivity (ENCC, Track 1 of 5) (Cisco U. login required)
2: Cisco SD-WAN Design Guide