"A software development team is not a group of isolated individuals working alone; each team member’s work output is a function of work output from all their teammates, not to mention several meaningful non-measurable interactions throughout the day. "
Amen to this. From "Can developer productivity be measured?" to which the TL,DR answer is: no.
https://stackoverflow.blog/2020/12/07/measuring-developer-productivity/
Another great point from the same article: "There’s a lot here that depends on human beings rather than trend charts and raw data. This is an inescapable fact of software: it’s far more about humans than ones and zeros, and always has been. Productivity tracking tools and incentive programs will never have as great an impact as a positive culture in the workplace. And when accountability and healthy communication are baked into this type of culture, critical moments for productivity will quickly become visible to the people most able to address them."
@schaueho
One other thing to note is the fact that humans do some of their designing and implementing in downtime. Sometimes it's a general chat away from the work area or physical office that unstick things. It's also what makes handovers and knowledge capture hard in tech. Sometimes someone doing their role doesn't consciously realise they are doing a thing which makes the task easier.