question mark is flashing

According to Apple:

A folder with a flashing question mark means that your startup disk is no longer available or doesn't contain a working Mac operating system.

If the question mark is persistent, and your Mac does not start up normally:

1. Press and hold the power button on your Mac for up to 10 seconds, until your Mac turns off.
2. Every Mac has a power button. On notebook computers that have Touch ID, press and hold Touch ID.
3. Use Disk Utility to repair your startup disk. Follow the steps for a Mac with an Intel processor.
4. If Disk Utility found no errors or repaired all errors, reinstall macOS.

Need more help?

• Chat now or call 1-800-APLCARE.
• International Support.

Scrolling to: "Question mark on the startup screen" jn Apple support's article:

If your Mac doesn’t start up as expected – Apple Support

says:

"If you have a Mac with Apple silicon and it experiences startup problems, try using macOS Recovery. See Use macOS Recovery on a Mac with Apple silicon."