A complex system that works is invariably found to have evolved from a simple system that worked.
Complex systems designed from scratch never work. Complex systems are rarely built all at once.
To build a complex system that works, start with a simpler system and improve it over time.
That is why most teams especially in software follow the agile method of working in iterations. You first the beta/basic version then v1.0, v1.1, v1.2, etc. with small changes through user feedbacks or internal team suggestions.