MacBook Air 2017 keeps randomly shutting down

I called Apple Helpline:

I reset the NVRAM by holding down Option - Command R and P keys for 20 seconds after pressing the power button.

Then I shut down and ran diagnostics by pressing the power switch and holding down the D key.

A language selection comes up.

Select your preferred language and the diagnostics will run automatically and give you a report.

Mine didn't show anything amiss - no errors.

I then shutdown the MacBook Air again and restarted in Safe mode (press power key and hold down the shift key until the Apple logo appears).

Then log in as normal.

If the issue still persists in Safe Mode the OS will need to be reinstalled.