MacBook M1 (2020 models and later) SAFE MODE ACCESS = How To Instructions are within this post.

• How to use safe mode on your Mac - Apple Support

https://support.apple.com/en-us/HT201262

How to use safe mode

Determine whether your using a Mac with Apple silicon, 

then follow appropriate steps for either of two type macs

as both are covered adequately in above support article.

• Apple Silicon SoC

1. Shut down your Mac.
2. Press and hold the power button for 10 seconds as your Mac starts up.
3. Release the power button when you see startup options window.
4. Select your startup disk, press and hold the Shift key, click Continue in Safe Mode, then release the Shift key.
5. Log in to your Mac. You might be asked to log in again.

• Intel-based processor

1. Turn on or restart your Mac, then immediately press and hold the Shift key as your Mac starts up.
2. Release the key when you see the login window, then log in to your Mac. 
3. You might be asked to log in again. On either the first or second login window,

you should see ”Safe Boot” in the upper-right corner of the window.

{.Above article further suggests additional steps should issues remain.

Below, a repeat in brief follows. Similar steps; provided by owc blog.}

• How to Start Your M1 Mac in Safe Mode | owc blog

https://eshop.macsales.com/blog/71023-start-your-m1-mac-in-safe-mode/

A. How to start your 'M1 Mac' in Safe Mode

1. On your Mac, choose Apple menu () > Shut Down.
2. After your Mac shuts down, wait 10 seconds.
3. Press and hold the power button until the startup disks and Options appear.
4. Press and hold the Shift key, then click Continue in Safe Mode.

B. How to start your 'Intel Mac' in Safe Mode

For comparison’s sake ~ the steps for an Intel Mac:

1. On your Mac, choose Apple menu () > Shut Down.
2. After your Mac shuts down, wait 10 seconds.
3. Restart your Mac, then immediately press and hold the Shift key.
4. Release the Shift key when you see the login window.

That would be either a M1 MacBook Air or a M1 MacBook Pro, as there are no M1 MacBooks.