NET Blazor’s vs. React

 Beyond JavaScript: Exploring .NET Blazor’s Challenge to React | by Sascha Klomp | Oct, 2023 | ITNEXT

NET Blazor is an open-source web development framework which was created by Microsoft in 2018. This framework is used for building interactive client-side web UIs using .NET and C# (compiled to WASM = WebAssembly) It can be considered a descendant of Razor pages, which was previously used with an MVC approach for full stack .NET development.
Blazor has been made with modern web development in mind, supporting a couple of different scenarios:

• Server-side rendering by pushing DOM diff updates through WebSockets
• Client-side rendering by running in WebAssembly (WASM) and updating the DOM through JS interoperability
• Hybrid implementation by integrating Blazor with native desktop and mobile frameworks MAUI or WPF

Blazor is supported by the most popular modern browsers.

Microsoft is using React

Use Office UI Fabric React components in your SharePoint client-side web part | Microsoft Learn

microsoft/fluentui: Fluent UI web represents a collection of utilities, React components, and web components for building web applications. @GitHub