I've spent hours that should have been minutes trying to make sure Rust doesn't re-build unnecessarily inside CI, so you don't have to.
You may not need Flux/ArgoCD or any fancy automated reconciliation loop deployment process just yet! Plain old CI runners work quite well for simple automated deployments (this approach powers this blog right now!).
Running containers for your dependencies during CI E2E tests in the background, without services
It took way more trial and error than I expected to set up E2E testing for a python-based project on CircleCI -- my loss (of time) is your gain.