The best advice I can give you there is to contact your hosting company on server performance issues.
Its quite a common misconception that having a lot of x will solve y. It is the configuration of such items generally you would need to be looking at, and that is an optimisation thing on your server. And there are far too many variables for us to be able to give you a simple answer. This is why we have a cloud environment. So people dont have to think about these things (and in our experience, most just want to run their site).
As a start, I would advise taking a step back and questioning what you have done already
NGinx - Why?
Redis - Are you sure you need it? Is the overhead speeding things up, or slowing it down?
mySQL - Is it configured to use the resources you have?
Cloudflare - What items do you have set up, and are some of those items potential overhead on initial load?
opcache - Is this configured correctly, or is it slowing things down?