Some time ago I made a tutorial about character customization for Unity, using the method of mesh substitution. This tutorial can be seen here.
This tutorial evoluted to an asset that now uses two different methods and have a database to store all information about the clothes, props, and the body structure.
This asset is available as open-source at GitHub: https://github.com/keawstudio/Clothing-System-3D.
In our Youtube channel you will find some video tutorials, showing how to use the system: https://www.youtube.com/c/Keawstudio
The vídeo below shows all the features available in this first version of the asset.
And two video tutorials showing how to use the system: