After updating to 17.3, there's no option for Stolen Device under Face ID & Passcodes

Hello ~ Click on below and review the information there…

About Stolen Device Protection for iPhone - Apple Support*

*How to turn Stolen Device Protection on or off

To turn on Stolen Device Protection you must use two-factor authentication for your Apple ID and set up or enable the following on your iPhone: a device passcode; Face ID or Touch ID; Find My; and Significant Locations* (Location Services). 

You can turn on Stolen Device Protection in Settings:

1. Go to Settings, then tap Face ID & Passcode.
2. Enter your device passcode.
3. Tap to turn Stolen Device Protection on or off. 

If you try to turn off Stolen Device Protection when you’re not in a familiar location, a security delay starts before you can turn it off. You should turn off Stolen Device Protection before you sell, give away, or trade in your iPhone.

~Katana-San~

Stolen Device Protection depends on biometric identification to protect your Apple ID and content, so if you don’t have Touch ID or Face ID (depending on your model iPhone) set up the option won’t appear.

Hello once more~ It’s still very new but have a look at this discussion… do you have a fingerprint set up?

I don’t see Stolen Device Protection with… - Apple Community

Keep in touch here as I can get some extra help…we won’t leave you hanging!

~Katana-San~

Hello ~ Do you have Location Services toggled on? Find My? Two Factor?

Turn Location Services and GPS on or off on your iPhone, iPad, or iPod touch - Apple Support

~Katana-San~

Hello~ That’s great. Good work!

~Katana-San~