Building a Secure and Scalable E-Commerce Platform

I am working on integrating an e-commerce platform for selling vintage watches and jewelry. What should be preferred for building a secure and scalable database to manage product listings? This may include used watches for men, vintage jewelry for men and women, and luxury items. This may include the support for tracking inventory, orders, and customer data. How can I ensure the system is optimized for fast queries and handles high traffic, especially during peak shopping seasons?

I am asking it as I am currently working on one of the dream project of my life. So, budget is not an issue for this one.

Your responses will highly be appreciated.