K8s is great if you have a SaaS product that you need to duplicate for each client where they need a dedicated instance, database, file system, etc. and you can automate it all and tie it into a ERP system. It’s way overkill for an e-commerce site. Best thing for a high volume website is NGINX, PHP-FPM maybe running Laravel, local Redis and a MySQL or Postgres cluster.

NGINX is pretty easy to set up load balancing with upstream backend too.

CI/CD can just be GitHub and some shell scripts.