Why is my screen displaying a black screen and question mark sign?

This usually indicates that it either doesn't see it's internal drive, or doesn't have one installed.

However if it doesn't recognize a present drive, repair is going to be extremely difficult because the ssd is soldered onto the logic board.

Try starting up into recovery by pressing the power button and holding Option-Command-R until a globe appears.
This should allow you to get access to some utilities to check your drive.

Well you can try the following methods to fix the issue you are facing:

1. Press and hold the power button on your Mac for up to 10 seconds, until your Mac turns off.
2. Use Disk Utility to repair your startup disk.
3. If Disk Utility found no errors or repaired all errors, reinstall macOS.

Try this. Shut down your Mac.

Press the start button and IMMEDIATELY press the following 4 keys until you see a startup screen. (You may want to practice your finger positions before you begin because this can be tricky and you have to move fast.)

OPTION + COMMAND + SHIFT + R

You must hold all 4 keys down until the startup screen appears. If a finger slips off you'll need to start over.

You should be presented with an option to restore over the internet. Select your internal drive (if it's shown) and follow the onscreen prompts to reinstall the version of MacOS that came with your computer. You will need a network connection for this to work.