Is @angular/flex-layout deprecated or no longer compatible with Angular 18?

Ans: Yes, you can check the deprecation on @angular/flex-layout - npm.js. The last version published is 15.0.0-beta.42 so it will work only up to Angular 15.

What are the recommended alternatives for responsive layout in Angular 18? Is there any migration guide from fxLayout to CSS/Tailwind/CDK?

These are the details provided in their GitHub repo:

NOTE: The Angular team no longer publishes new releases of this project. Please review this blog post for alternatives, and this article for the explanation and next steps.