M365 Engineer folks, a career question for you.

I work as a M365 Engineer with my focus on Exchange Online, MDO, Proofpoint and Powershell. What niche skills should I learn which will help me grow further would be great in next 5-10 years. I would like to keep my primary skills within M365 and Email as i have invested a lot of years in learning and gaining competency and would like to explore more skills related to this or close to this.