FreeBSD in 2023 is still masquerading as "Microsoft Windows NT" in order for things to work correctly. It has been this way since 2004. It works fine in "Windows Land" because the hardware is literally special-casing behavior for Windows!
/*
* OS name, used for the _OS object. The _OS object is essentially obsolete,
* but there is a large base of ASL/AML code in existing machines that check
* for the string below. The use of this string usually guarantees that
* the ASL will execute down the most tested code path. Also, there is some
* code that will not execute the _OSI method unless _OS matches the string
* below. Therefore, change this string at your own risk.
*/
#define ACPI_OS_NAME "Microsoft Windows NT"