Q: My mac can't boot

Have you reset the NVRAM yet? This can sometimes resolve issues with the folder/question mark you are seeing.

Try this before reinstalling if you haven't already

How to Reset NVRAM on your Mac - Apple Support

Sorry to hear my friend.

Sounds like you are actually having hard drive issues. You will probably have to tough it out and set some time aside to get the hardware checked out at an Apple Store. I don't think there is anything else we can help you do here.

If you can't repair the hard drive, it is most likely failing.

You can try fsck to repair the disk, but after that, there really aren't any other options.

Resolve startup issues and perform disk maintenance with Disk Utility and fsck - Apple Support