Sr. Server Administrator to setup Production SaaS POS Infrastructure

We are looking for an experienced Server Administrator / DevOps Engineer to take ownership of setting up a production-grade infrastructure for one of our SaaS-based POS systems. This is not just a basic server setup. We need someone who understands security, scalability, reliability, monitoring, backups, deployment and production operations. We particularly value someone who can think like a production engineer, not someone who simply installs packages and follows instructions. You should be able to explain: How you would secure the infrastructure How you would handle backups and disaster recovery How you would minimize downtime during deployments How you would monitor server/application/database health How the infrastructure can scale as the number of POS customers increases