"Under aegis of" is a phrase that has long been used to indicate support or protection from a higher authority. However, there are many synonyms for this phrase that can add a more nuanced meaning to your writing. "Under the auspices of" is one alternative, which suggests that the higher authority has given permission or approval for the action being taken. "Under the protective wing of" sounds poetic and can suggest a more personal relationship between the two parties. Other options include "with the backing of," "under the guidance of," or simply "supported by." Whatever your intended meaning, there are plenty of ways to convey the idea of support and protection in your writing.