Leadership is the single most important department in any business.
In my view, if you seek to delegate or outsource this department you are essentially abdicating all responsibility for the business delivering on the plan.
Of course most people don't delegate or outsource this role – they simply neglect it as they just have TLT. They are in denial and they make excuses as to why they can't lead well.
If this is you then put the leadership hat firmly back on and find the other hats you need to take off. Then, as leader, it is your job to empower others in your business to step up and manage the other departments.