I think the biggest tradeoff here is putting Lambda into private subnets without showing a clear egress or endpoint strategy. I see VPC-attached Lambdas, DynamoDB, Secrets Manager, CloudWatch, and SQS, but no NAT Gateway and only a generic VPC endpoint security group. In production, this often becomes the failure point: functions time out on cold start, can’t reach AWS services reliably, or create hidden operational coupling to endpoint coverage. If you intend to avoid NAT cost, I’d want explicit interface/gateway endpoints for every dependency and clarity on DNS, routing, and security group rules. I’m also concerned that API Gateway appears public with no mention of WAF, authorizers, throttling, or usage plans. That makes abuse, cost spikes, and noisy-neighbor traffic a real risk. Finally, alarms are too thin for production; latency and Lambda errors alone won’t catch DLQ growth, SQS backlog, DynamoDB throttling, or KMS/Secrets access failures. I would tighten the network design first, because that’s where availability and debugging pain will show up fastest.