Earlier quoted context omitted.
Same for me. I think we are all talking like we work on the exact same product. I work at an agency with many codebases, from different clients. Some we inherited that don't yet have good coverage, some with notoriously brittle third party integrations we can't truly test until it is in the live data environment, and some with clients who are very unresponsive and if we planned a Friday deploy the chances of a no-go…
It sounds like you're deep into scenario 2. The mention of "sign off or testers" is a dead giveaway. "testers" being people not automation. likewise "sign-off". It also sounds like while you know that better exists, the "commercial reality" is "not on this project". I've been there too. I don't see this as being in conflict with what I said above.
Arrgh, I meant to say, "scenario 1" - the second scenario.
The first scenario is numbered 0, because it has zero process.