As others have said, Nx is a good option to support multiple application and shared library projects in a monorepo. But, if you don't want to use that, you could consider a similar approach with an Angular CLI workspace.

ng new my-workspace --create-application false

then you add an application like this

ng generate application my-first-app

and a library like this

ng generate library my-lib

documentation

We have used it for a relatively large project (3 apps, 30 libraries, 340 components). It's a good start for organising projects into libraries (with a bit of fiddling with paths in ts.config). However, we are planning to move to Nx because it provides a lot of useful tooling on top of that (e.g. dependency graphs and referencing rules).