There is no way to answer this question without knowing more about what that product is. If that product can be well-served with a customized wordpress templat

There is no way to answer this question without knowing more about what that product is. If that product can be well-served with a customized wordpress template (or similar off-the-shelf CMS), that's probably what you should do. If that website requires process tons of data in real-time, that pushes you to a different stack. If that website requires storing and processing tons of data, but processing can be batched, different stack. If that site is an interactive game, different stack. Do you need to stream data? video? process large uploads? Should it work offline? Should it work on multiple devices that are offline at the same time and sync up later? Is it mainly mobile? Is it a big enterprise-y application? Mainly consumed by teenagers on mobile phones? Serving a population in rural Brazil / India / Bangladesh? You could go on like this for quite some time. I certainly have my preferences, like any dev, but the needs of the project are going to dictate what's needed.