An error with code 1001 during the configuration of a time-based firewall rule often indicates a time synchronization issue. Restarting the NTP service on the ESXi host can resolve this issue by ensuring that the host's time is synchronized correctly, which is essential for time-based rules to function accurately.

Source NAT (SNAT) is used to translate the private IP address (172.16.101.11) of the NAT VM to a public IP address (80.80.80.1) as the packets leave the NAT-Segment network. SNAT changes the source IP of outbound packets, allowing private IP addresses within the internal network to be mapped to public IP addresses for communication with external networks.

Configure ECMP on the Tier-0 gateway: ECMP (Equal-Cost Multi-Path) allows multiple paths for traffic between the Tier-0 Gateway and the upstream physical routers, effectively distributing the traffic load and improving throughput. By enabling ECMP, you can reduce congestion and increase bandwidth utilization, thus addressing performance issues.
Deploy Large size Edge node/s: Deploying larger Edge nodes can provide more resources (CPU, memory, and network interfaces) to handle higher throughput and reduce congestion. This is especially important if the existing Edge node is overwhelmed by the amount of traffic.

https://docs.vmware.com/en/VMware-NSX/4.1/administration/GUID-69604E49-BC8B-4777-BFD8-B98F8D1FF064.html

IPSec VPN services can be configured at Tier-0 and Tier-1 gateways: In NSX, IPSec VPN services can be applied to both Tier-0 and Tier-1 gateways, allowing secure site-to-site connections from these gateway levels.
IPSec VPNs use the DPDK accelerated performance library: NSX leverages the Data Plane Development Kit (DPDK) for optimized performance, which accelerates packet processing for IPSec VPNs and improves throughput.