Are there any public examples of a complete real-world IT infrastructure that I can study?

I'm looking for something like a sanitized/anonymized documentation set of a real or realistic company environment, showing things such as:

Overall infrastructure / architecture

Network topology and connections

Servers and their roles

AD / DNS / DHCP

Firewalls and network segmentation

VLANs, subnets and routing

Internet/ISP connectivity

Applications and how they communicate

Storage and backups

Cloud + on-premise connectivity

Security architecture

How users/devices connect to the infrastructure

Monitoring and IT operations

Basic workflows and dependencies

Basically, I'd like to see how all these pieces fit together in an actual business, from the user's computer all the way through the network, servers, applications, Internet, backups, security, etc.

I understand that a real company's exact configuration, IP addresses, firewall rules, credentials, etc. would obviously be confidential. I'm looking for public examples, lab environments, case studies, architecture diagrams, documentation templates, or sanitized real-world infrastructure documentation that I can study.

If you were learning system administration from scratch, what resources would you recommend for understanding the whole environment rather than just individual technologies?

I'd especially appreciate examples that show the complete picture and the relationships between components, not just a single network diagram.