Depending on your technical comfort level, you can use automated GUI tools, on-device apps, or command-line scripts. Automated Desktop Tools (Easiest)

insert_dylib @executable_path/your.dylib Payload/App.app/AppBinary

If you are not comfortable using the command line, Sideloadly provides the easiest graphical user interface (GUI) method to inject dylibs on both macOS and Windows.