Auto lock no more than 2 mints

Is your iPhone provided by your work? Do you have a work email account on the device? Is it managed by the company you work for? These are things that can cause the lock settings to change due to the requirements for some of them. On my iPhone 16 Pro Max, I have 3, 4, and 5 minutes above the 2 minute setting.

Do you have a work email on your iPhone? If so, it may have installed a profile that prevents you from leaving the phone unlocked for longer than that.