Processes in Microsoft 365 Insider for installing preview builds, activating subscriptions, and keeping apps up to date with the latest Insider features.
OK we've beat the install issues to death and ruled out just about everything. It's time to focus on the OS.
First, verify the startup volume
Repair a disk using Disk Utility on Mac - Apple Support
Then, make a new user account in Mac OS System Preferences and try again in the new user..