We have review environments so there is an easy way to have a fairly persistent config to QA features, but our environment that's named staging is more of a historical artifact. It's basically the same as a review environment because we recognize that after testing that the feature works as intended, it's going out and, we may be surprised by real production use. Our test suite, which is kicked off after you hit the merge button takes about 10-15 minutes and build/deploy to Amazon ECS is 8 to 10 minutes so there is pretty quick feedback. We also use feature flags when possible, but most deploys are very granular and we generally don't worry if something passes our test suite which is currently about 6k tests. Once we decided that merge to main get deployed automatically our staging environment became just another environment, our velocity increased, security patches are deployed almost immediately and we mostly don't worry about launches.