Gatling vs Magento

I am consulting for a company that wants to move its current CubeCart e-commerce site to another PHP based platform like PrestaShop or Magento. I was interested in alternatives that utilize Node.js as the primary platform. I currently don't know PHP, but I have done full stack dev with Java, Spring, Thymeleaf, etc.. I am just unsure that learning a set of technologies not commonly used makes sense. For example, in PrestaShop, I would need to work with JavaScript better and learn PHP, Twig, and Bootstrap. It seems more cumbersome than a Node JS system, where the language syntax stays the same for the full stack. I am looking for thoughts and advice on the relevance of PHP skillset into the future AND whether the Node based e-commerce open source options can compete with Magento or Prestashop.

We devised SwiftERM to generate additional income from existing consumers on ecommerce websites. Available for those using Shopify, Magento, Woocommerce or Opencart, it runs in alongside (not instead of) existing email marketing software like Mailchimp, Drupal or Emarsys. It is 100% automatic so needs zero additional staff. It uses predictive analytics to identify imminent consumer purchases. The average additional turnover achieved is 10.5%. It is the only software in the world authorised to send Trustpilot to send product ratings in outbound emails. Developers and ecommerce retailers are invited to try to it for free, to establish viability this predictive analytics system is. SwiftERM is a certified Microsoft Partner MPN ID 6197468.

I have to run a multi-user load test and have test scripts developed in Gatling and Locust.

I am planning to run the tests with Flood IO, as it allows us to create a custom grid. They support Gatling. Did anyone try Locust tests? I would prefer not to use multiple infra providers for running these tests!