Not impossible. even in a prescriptive framework like ISO 27001, adequate SOD is a judgement call between you and the auditor. Generally speaking, if a single dev can push a code change to prod, in a way that would escape audit or not require a second pair of eyes, that would not be compliant. So if a dev writing code, also manages the deploy environment, that may not pass muster.

But it's not that cut and dried. There are degrees of rigor.

No. Assuming a well configured continuous deployment type environment; you just need to have peer review on code before it can hit production, and you need to have controls in place over the who, what and when of elevated access to production being granted