How to translate a ready-made React SPA application to SSR?

Question

React

There is a small application. About 100 components, divided into conditional 10 pages. The application interacts heavily with the server. Store on Redux. What options are there (I've only found Next.js so far), what problems should I expect, and how difficult is it when moving from SPA to SSR? The server itself is on the C# ASP.NET Core 3.1 stack.