Not much is going to compete directly with React's ecosystem maturity.
But, of course, there's the option you have when using a non-React library in React: on mount, you instantiate the library in a ref, and then you use effects to turn reactive state updates into library invocations.
For example, wrapping https://datatables.net/ if there were no React adapter.
Wouldn't you mean that the other way around? So you have a Svelte/SolidJS application, and you use some React components like from MUI to fill the gaps.