I am currently maintaining and adding to a React app started in 2016. React is fine. 9 years of decisions by numerous people that are no longer working on it, and I can still improve and update it. I can even bring in developers with no experience on the code base to change things. I would change 75% of it now, but that is not a React problem, that is a normal development problem.

React is fine, it is stable, standard, and still works for almost any use cases. There are not many JS libraries that have stood that test of time.