VPC Lattice and TGW

For a multi-account, multi-region setup with database, Kafka, and third-party connectivity via Direct Connect (DX) or VPN, AWS Transit Gateway (TGW) is generally the better option for scalability, performance, and security, especially for high-throughput use cases. It's designed for large-scale network connectivity between VPCs and on-premises systems.

VPC Lattice, on the other hand, is great for service-to-service communication in microservices architectures, offering built-in traffic routing, service discovery, and fine-grained security for inter-service communication. It’s not as focused on network-level connectivity as TGW.

For scalability and security in large networks, go with Transit Gateway. For service mesh and microservices communication, VPC Lattice is a good choice. As for banks using these solutions, TGW is more widely adopted in traditional large-scale networking setups.

To add to Robin's answer, if you are working multiple VPCs and regions, it is better to use CloudWAN instead of TGW. I have used both TGW and CloudWAN, and managing network connectivity is unbelievably easy with CloudWAN. It's a centralised place for managing your global network. Refer https://aws.amazon.com/cloud-wan/