For Android Enterprise device in kiosk mode or not, whether or not an end-user can add any new google account is controlled by corresponding option in deployed feature-control  profile payload.  For example, adding any (i.e. not just "Google") account is disallowed, and thus the "Add account" region is grayed out in device's Settings as shown in the following device screenshot.  Tapping on the "Add account" area will result in the "Action not allowed" warning message being popped up.

For app that needs to allow end-user to choose between created accounts to sign in,  how the apps is written to get into the right GUI page to select the right user will determine if making a choice is possible or not    If you have problem to show/choose between different accounts for any apps on your device,  please specify your apps, device firmware version, and preferably include screenshot(s) to illustrate the issue.

If your device is in kiosk mode (lockdown menu) and  there is a need to add more Google account,  the "Manage accounts" Settings sub-page shown in the screenshot in my last post MAY be accessible with a MobiControl kiosk item

    launch://com.android.settings/.Settings$AccountDashboardActivity 

The right parameter may vary with device brands, models and/or firmware versions.    Also, even if this parameter is  OK for accessing the "Manage accounts" page,  please be aware that the GUI of this Settings page on some devices may create loophole(s) for device end-user to go to other Settings page(s), which may not be desirable for security reasons.

Having to change  Location Accuracy to High Accuracy in feature-control profile payload sounds a bit strange, and is quite sensitive in terms of  device end-user privacy and/or device battery-life//power-consumption.    Maybe you should contact the support team of the app to confirm under what condition(s) will the account choice be prompted.   Also, if the app is a free app, would you mind sharing the bundle-ID of the app so that some tests can be done?