ECS can be simpler if you stick to the default and use something like copilot - it effectively turns your compose file into a cluster with all of the networking etc
We used CloudFormation and ECS/Fargate to great effect at my last company. It simplified a lot, especially logging, networking, and IAM integration compared to Kubernetes.
The biggest downside was that it took quite a while to spin up new tasks (but that might be Fargate specifically) which hurt us when we were trying to do async things (and we wouldn’t be able to use lambda for many async things because the run time would be too long or the enormous bundle size for a small-ish Python task would exceed Lambda’s limits). It would also make deployments take longer than we wanted (we were really pushing the envelope for frequent, tiny deployments) especially in rollback scenarios.
The biggest downside was that it took quite a while to spin up new tasks (but that might be Fargate specifically) which hurt us when we were trying to do async things (and we wouldn’t be able to use lambda for many async things because the run time would be too long or the enormous bundle size for a small-ish Python task would exceed Lambda’s limits). It would also make deployments take longer than we wanted (we were really pushing the envelope for frequent, tiny deployments) especially in rollback scenarios.