Write it in React, and if you run into performance issues, there are a bunch of well-known performance optimizations you can make which are easy to discover. It's a well-trodden path that many engineers have walked before.
Write it in your own vanilla framework, and you will effectively re-invent all the complexity of React, but in a way that no one has ever done before. It's easy at small application scales, but once your app gets large, good luck debugging the thing that exists primarily in your principal engineer's head.
The fact that react is popular and has learning resources available doesn't change the argument: “immediate mode” that some boast as a React feature is an illusion that will end up hitting you, and you'll end up using it like any other retained state framework.
React is cool because it's widely used (hence more tooling and learning material) and because JSX is very convenient (it composes very well), not because the vdom works well to create an immediate mode API.
Write it in your own vanilla framework, and you will effectively re-invent all the complexity of React, but in a way that no one has ever done before. It's easy at small application scales, but once your app gets large, good luck debugging the thing that exists primarily in your principal engineer's head.