Software design at most tech companies and startups tend to be surprising than what you would expect in general. Most startups do not use any of the standard architecture plans - UML, 4+1 model, ADR, C4 or dependency diagrams - but simple diagrams. Most often than not, they do not employ hands-off IT architects or enterprise architects, but experienced hands who drive the design process. Lastly, majority of them do not follow any strict/common architecture patters, referenced in the software architecture literature.
The author notes that peer engineers at FANG companies tend to share a simple approach to design and implementation - simple, jargonless software design over architecture patterns
The author also shares few tips on getting better at designing systems
The best software design is simple and easy to understand. The next time you’re starting a new project, instead of thinking, “How will I architect this system, what battle-tested patterns should I use and what formal methodology should I document it with?”, think “How can I come up with the simplest possible design, in a way that’s easy for anyone to understand?”.