We are finding this to be more trouble than it's worth, starting from the set up experience.
Enabling GCC access in iOS requires the unituitive act of going into iOS settings to enable it and the link to enable GCC in Android is almost invisible. Users miss it even when it's on the screen.
Why can't a prompt to enable GCC acces be triggered automatically if you enter an email address that is a GCC tenant instead of the setup just failing?
The restriction to a single email account is too restrictive because it doesn't allow you to even add another GCC account from the same tenant in the app. We have users who need to access their own GCC account plus a shared GCC mailbox. So, to do their job, they have to use an activesync client instead which makes the iOS app redundant.
We are considering getting the "Government Community Cloud Bypass Waiver" to enable the functionality we need, but we don't fully understand everything that involves. If the waiver moves the entire tenant's data to less secure locations, that seems extreme just to make the Outlook app work the way we need it to.
Most of our users are using the native iOS and Android active sync mail apps instead because the Outlook app is so restrictive that it isn't even worth using.
Some of these settings need to be more configurable by the tenant without going to the drastic measure of having to completely abandon GCC to make a single app work.