You can make a React app that's wildly different to all the others, but if you follow "best practises", and you learned from the same tutorials, and you're using the same component libraries as other React devs your app will probably drift towards looking and working like other React apps unless you make a conscious choice to stop that happening.

Yeah, one difference between React and, say, Unreal Engine is that Unreal Engine is the brand for the whole package while React is the brand for one of the core components. ("I'd just like to interject for a moment. What you're referring to as React is, in fact, React/Redux/Tailwind...")

Once you've bought into the whole ecosystem, you get an "engine" that wants your app to look and work a certain way just like how Unreal wants your game to look and work a certain way. You can customize it however you want, but every decision you don't make is made for you by the engine.

And even when you are making the decisions, the engine is always there, nudging you in a certain direction by making some things easier than others.

There is some truth.m to that. Tutorials need to decide where to focus on React but want to make you feel like you are building something cool so they will bring in style frameworks to assist so you can focus on the react.

I assume this is also true for jquery/angular/vue and other library tutorials.

Maybe just for fun they should use alternative frameworks!

Then on the job, well unless you are a designery company it will be devs who do design and will happily delegate that thinking to a framework. Again not a react thing but a general dev thing.

I have seen this too in desktop apps of 90s. Just use MFC or some popular toolkit.

That is just not true, no matter how hard you try to make it seem that way.