Library Versioning best Practise

i have source code libraries in different Versions.
What is the best practice for integrating the different versions in different projects?
For example:

A-Lib Version:1.0.0
A-Lib Version: 2.0.0

Target Program A-Program consume A-Lib 1.0.0
Target Program B-Program consume A-Lib 2.0.0

I would recommend to start using a package manager, such as vcpkg, but that might be a bit too complex, especially if those “different projects” are actually sub-projects of one common project.

Without a package manager you can probably get away with just the following (assuming that A-Lib has a proper CMake package, which includes a version config too):

find_package(A-Lib 2.0.0 CONFIG REQUIRED)

plus the ability to customize the version selection.