Design of 3D modular organisers for production

I am looking for an experienced designer to create a design for modular organisers. The design should include complete 3D models of the individual modules, which can be easily combined and configured by users. The organisers are to be designed with mass production in mind, with customisable colours and layout.

Design requirements:

Design of modules for 3D printing (STL files) and for production (CAD files, e.g. STEP, IGES).

Modularity: ability to easily combine modules in different configurations.

Aesthetics: modern, minimalist design.

Connection system: stable, intuitive connections (e.g. snaps, magnets).

Consideration of ergonomics and functionality.

Technical documentation and assembly instructions.

Budget: Please give me an estimate of the cost of the project.

Possibility of long-term cooperation.

A portfolio with similar projects is welcome.