Simple and very Secure Lottery (bet) Site

I am seeking a freelancer to design a betting website, specifically a straightforward lottery system, with a substantial emphasis on security. It's crucial to engage with a professional who possesses deep knowledge and experience in the field.

The visual appearance (front end) of the site will be straightforward and uncomplicated. However, it's vital that all technical aspects, such as database management, payment methods, security, server, speed, integration with payment gateways, and withdrawal system, are executed flawlessly and safely. I am looking for guidance on best development practices, hosting strategies, and measures to ensure the system remains efficient and secure.

My topmost priority is to ensure the site's operability, speed, and above all, security. It's paramount that client funds remain unhackable, and all aspects related to the database, login, and payment methods are safe for users.

Necessary requirements:

HTML
NoSQL Couch & Mongo
XSS (Cross-site scripting)
PostgreSQL
Database Development
Web Security
API
Azure
Cloud Security
SSIS (SQL Server Integration Services)
Full Stack Development