Segregation of duties is going to PREVENT users from having the ability to potentially manipulate processes within the business by splitting duties amongst others. Somewhat of a "checks and balances" kind of system.

Lighting will illuminate the area, detect people attempting to be under the cover of night, and deter them from committing unwanted acts. Furthermore, a sensor will detect movement in an area, and sensors that are visible can ward off any potential bad actors.

Port security is the best solution to prevent unauthorized devices, like a visitor's laptop, from connecting to the company's network. Port security can limit the number of devices that can connect to a network switch port and block unauthorized MAC addresses, effectively stopping unauthorized access attempts.
* Web application firewall (WAF) protects against web-based attacks, not unauthorized network access.
* Transport Layer Security (TLS) ensures encrypted communication but does not manage physical network access.
* Virtual Private Network (VPN) secures remote connections but does not control access through physical network ports.