As for the gigantic monolithic codebase, a proper build environment will know (to some degree) what tests could be impacted and only run those in CI. And if yo

As for the gigantic monolithic codebase, a proper build environment will know (to some degree) what tests could be impacted and only run those in CI. And if you have segmented your tests in fast and slow, you can always invest in the proper infrastructure to only require fast tests to pass before CI and have some degree of automatic rollbacks (or supervised) when slow tests break.