Screen Lock Intervals

I have an iPhone 8 and am trying to prevent the screen from locking as a result of inactivity after a minute. In the Display & Settings > Screen Lock section, there are only options for 30 second and 1 minute intervals to change to. Why do I not have 2 minute, 5 minute, Never, etc?

Note: this is a company phone, and buried deep somewhere online, someone mentioned that my IT admin may have set it. But I spoke to IT and they say it is an Apple issue.