These tools are way too young for anyone to have actually spent a lot of time using them.

Bun is bundling everything and making it really fast, while also striving to maintain as much compatibility as possible with Node. It doesn't throw away the existing ecosystem.

Deno took on too much of an adversarial perspective towards the Node ecosystem and now they're working towards re-adding support.

So in terms of a successor, I'd say the only option is Bun because it's still trying to maintain compatibility with Node while innovating with new features.