When I work places where interruptions are expected I change how I do my work. So an observer may see them costing me less time but that’s amortized across the rest of my work as a consequence of leaning into interruption. It’s still there, it’s just spread out more.
At the most disruptive place I finally arranged it so I worked at home on Fridays and Monday through Thursday were used to answer questions, attend meetings, do shallow work and do exploratory work for deep work. For instance, you need to do a refactor for a new feature or a bug fix. Is the code going to just let you do it, or will this change require another, and another, and another to get things working again?
So most Fridays I knew exactly what I needed to do and I coded for a solid six+ hours. And having already poked around I typically got about twice as much done in that time as I typically would in a day.
Oof, I don't think I could be successful at a place like that. Only 6-ish hardcore-productive hours of coding per week would make me sad. I would want to invert your arrangement: I'm in the office Monday to answer questions and interact with people, and Tues-Fri I'm at home doing deep work.
(I know that's unrealistic. But that would be my ideal.)
This is a great point and a lesson that has taken me decades. If you aren’t given quiet uninterrupted time the company is signaling to you that office time is about managing day to day fires, not deep work.
Often you need to protect time to get something done but they literally want you to be doing something other than writing 10k LOC.