If you're a senior dev, you should be gaming the system a bit to create the time needed to fulfill your role. Never let the keeners fill your time up to 100%, unless it's truly neccessary. There's always going to be some infrastructure that needs fixing, research that needs doing, refactoring that should happen, etc. And you should always have some slack for mentoring and whiteboard discussions.
I almost always start an agile sprint with a self-generated task or two already in my queue for just this reason.
Nurturing employees, and indeed software quality, is the product of company and team culture.
The development process is concrete (and “SMART”), so that’s what many managers focus on. The cultural aspects are more nebulous, so they are ignored.