Using a temp agency
Temps aren't all secretaries and admin staff. Some temp agencies specialize in specific fields, sometimes being a hybrid form of recruitment and temp agency. Professionals also have their equivalent to find lawyers, tradespeople, and even dentists, doctors and nurses. That arrangement, for the agencies, works well because they can work with a range of employer vacancies, and not be limited in their own range of services.
As contracting jobs becomes more common, the temp agencies are evolving. The new employment market works very much to their advantage, with ranges of short-term jobs like project jobs providing a big opportunity for placements. A project, for example, will set itself up with a finite time frame. The project manager, to save time and money, will simply go and hire the admin staff as a package deal. It takes a phone call to do, and there's no fuss.
If you're looking for flexibility, and need some space in your life to manage your work, a temp agency may well be the solution.