After leaving Amazon you really go on to understand how good the internal tools are at Amazon and how they probably have the best tools in the industry.
Our team was abandoning Apollo for MAWS, so our deployments were bridged between the two, resulting in another twisted pile of incomprehensible script-glue.
Pipelines was ok (!)
Everything on public EC2 for managing deployments (CodeDeploy and CloudFormation in particular) were so broken and bug-ridden and non-performant that we couldn't reliably deploy production code with them.
I prefer open source solutions in almost every way. I actually can't think of a single problem that the Amazon internal stack solves that isn't better solved in the open-source world. Which isn't surprising, given the constraints involved.
Brazil's dependency model is, I think, very much worth rethinking. Just try to use it for NodeJS. Apollo is fine but slow and dated and needs love. Pipelines works for specific software models and not others (ever seen a pipeline with 500 envs?). Great design for building custom approval steps though (long ago I wrote a now-popular one).