Hey there,
It sounded like you're very interested in using the latest technologies and having the best performance and providing the best user experience possible.
In projects like this we always tend to develop everything from scratch, what that means is we won't use any CMS like Wordpress, or any bloated library or framework, we'll stick to the basics; we'll code everything from scratch.
Our goal is to separate the front-end from the back-end. We do that using a REST API.
We'll develop an advanced REST API with the latest version of PHP, this will open a lot of doors for us, maybe a mobile app in the future or partner access, etc.
We'll use Vue.js for the front-end, it's literally the fastest out there, and will also yield a very small distribution build that loads really fast.
Why stop there? We'll set this up on an AWS auto-scaling group. This means the website will be running on multiple servers, instead of one, the traffic will be managed by a load balancer and each server will handle some of that traffic, this way the website won't ever lag and your users will have a great user experience.
I want to work on this and I would love to discuss it further with you,
Looking forward to it,
Mario A.