I ran into a similar situation only days ago with my MacBook Air. The fix was to repair the startup drive with Disk Utility First Aid. It sounds complicated, but is fairly simple.
Startup your computer in macOS Recovery mode.
Use macOS Recovery on a Mac with Apple silicon - Apple Support
Now, while still in recovery mode, launch the Disk Utility application.
In **, click View > Show All Devices.
Select each internal item listed in the ** sidebar and run First Aid on it. Start from the bottom with the APFS volumes, then the container disk and then the drive media itself.
The steps to repair your computer's internal storage are included in the document linked above.

When that is done, shut down the Mac, reboot normally and check your ability to turn on Find My.