An easy mistake to make as a manager is to assume delegation is management.
Finding a great candidate to run a portion of your portfolio isn’t the job. You need to then be able to influence this candidate to shape their thought process, improve their skills and ability to have an impact, and, where possible, provide wisdom and insight that helps them become more effective.
Learning to hire good people and then to delegate is an important step in the process of becoming a manager. But it is just one of many.