Earlier in my career I was a manager of a team of 12 direct reports (non-tech white-collar industry) and it wasn't that difficult to do on top of my normal work

Earlier in my career I was a manager of a team of 12 direct reports (non-tech white-collar industry) and it wasn't that difficult to do on top of my normal workload. Of course, as a manager my normal workload was reduced to account for the managerial tasks, because that's what most industries outside of tech do.