Upcoming Exchange Online Device Access and Conditional Access changes with Outlook mobile

Microsoft mobile solutions are becoming mess.

Customers looking to manage Outlook for iOS and Android have the following options:

1. Recommended: The Enterprise Mobility + Security suite, which includes Microsoft Intune and Azure Active Directory conditional access.

2. Mobile Device Management (MDM) for Office 365 (free/builtin?). "MDM for Office 365 provides device management capabilities at no additional cost"

3. Third-party Mobile Device Management solutions.

4. Mobile Device Access and Mobile Device Mailbox Policies (free/builtin?).

https://docs.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/outlook-for-ios-and-android/manage-outlook-for-ios-and-android#options-for-managing-devices-and-applications-in-office-365

"Create rules that allow Outlook on Windows devices for Exchange ActiveSync connectivity (WP refers to Windows Phone, WP8 refers to Windows Phone 8 and later, and WindowsMail refers to the Mail app included in Windows 10)"

https://docs.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/outlook-for-ios-and-android/secure-outlook-for-ios-and-android#leveraging-exchange-online-mobile-device-policies

3 solutions from Microsoft for managing mobile devices, but there is no good diagnostics tool explaining what's going on.

The_Exchange_Team 

my question: The Microsoft built-in Mail app (Mail and Calendar in MS Store) - will it be affected? how it should be managed? Which Conditional Access policy should be used? Yes, this is enough for some of our users, as they don't need full Office package price (security bonus: all Excel/Word macros are "blocked" 😊).