From what I can tell Google is involved in this directive to move away from secure settings usage so even if it were possible for Zebra to do that, it's unlikely that they would due to the strong partnership and alignment with Google. 

Well aware of the fact Zebra and Google want to head in that direction. 

What I'm proposing here is a solution in the meantime, until Zebra or Google implement a way to apply these settings. 

I just want to share our solution of accepting the Writesecuresetting permission without exposing the whole Settings application or have the user be outside of the lockdown or anything else weird.

You will still need to accept the setting manually but you don't need to fight with accepting it :)

Add the following to the lockdown template, as a hidden post, don't map the MCLink in the template.

Launch://com.android.settings/.Settings$AppWriteSettingsActivity

Just to supplement what Johan said,  some devices may instead have the "Write System Settings" permission configurable using another activity that can be started in lockdown menu with

  Launch://com.android.settings/.Settings$WriteSettingsActivity

It is also worh mentioning the drawback or potential risk of using this approach in lockdown menu.  While it is OK to have such item in the lockdown menu while preparing the devices for deployment to end-users, leaving this in the lockdown menu after deployment to end-user may cause problem because end-users can toggle the permission off anytime, especially when they do not want IT to silently change various device settings and infringe their privacy.