Why is Microsoft 365 setup (Groups + SharePoint + Domains) still so complex?

Three of your points are documented behavior, not bugs. Groups created in Teams are hidden from Outlook and the GAL by default fix with Set-UnifiedGroup -HiddenFromExchangeClientsEnabled:$false and -HiddenFromAddressListsEnabled:$false. SharePoint sites do provision automatically, just asynchronously (minutes to 24 hours), so yours wasn't missing it wasn't ready. And permissions only flow one way: group owners become SharePoint admins, but SharePoint owners don't become group owners. [

The rest of your list stands   no warning about the Teams/Outlook split, no provisioning indicator, no required-vs-optional DNS clarity, no single setup status view.

Practical fix: pick one creation surface and stick to it, don't use aliases instead of real users, and wait 24 hours before assuming something broke. Send it to the M365 feedback portal as discoverability feedback  support will just close it as "by design."