I haven't necessarily found something that works well for me as such, but it's a plausible equilibrium for now and I see paths to improving it.

Small children do interrupt, as a fact of life. Depending on what I'm doing I will chase them with various degrees of impatience, or take the interruption if I wasn't doing anything too deep. Sometimes I shut my study door if I really can't be interrupted (e.g. during a meeting), though I prefer not to most of the time. Even so: an interruption from one of my children is ultimately much less distracting than one from a co-worker who has something like a complicated boot loader problem they need me to investigate; something like that will definitely require dumping all my mental state.