I lost everything

We don’t know what are the specs of your PC, so even if think that your PC is good, it might be low powered for your project. But here I think the specs doesn’t matter, it’s related to shotcut.

What version are you using of shotcut (Go to Help>About), this was also discussed in this topic

The project was trying to contain itself in that
Case.

You should go to View>Application Log and see for some errors there and this might help, also check the log file of export, by right clicking the export job and then click view log.

Are you running a file type that is not supported by shotcut?