Any advice on how to improve operational efficiency in software delivery? Looking for insight in how to trim time without compromising code quality.

Few additional things other than what is already mentioned by Younes and John. 

- Ruthless de-prioritization of the features/stories, which do not add value. This is most crucial to focus on delivering right things. 
- Taking a longer term, end to end view of the delivery. Additional time spent in writing unit tests and building TDD culture will help in significantly reducing the time spent later on fixing bugs (rework)
- Focusing on design principles for e.g. SOLID principles will a go a long way in ensuring technical debt is under control. 
- Continuous Learning Culture will be foundational to operational efficiency improvements. 

As Younes mentioned, smaller work items.
Try to get them atomic and quick.
I strive for 1 to 3 days max so we can visualize the work moving, and as soon as something is "in progress" for more than 2 days, we start asking each other how we can help.

Make sure to incentivise quick With quality.
Too often, efforts to increase speed become an exercise in accruing tech debt.

Frequent (weekly) demonstrations from the team to stakeholders helps.
Push for scope negotiations in those talks.
Make stakeholders aware of what "just one more tiny ask" will do the schedule.

Smaller teams, smaller and simpler stories as close to 1 requirement per story as possible. automate your testing and of course us CICD!