My solution for "Failed to open document"

What version of SketchUp are you really using? Your profile says SketchUp for Schools 2021. SketchUp for Schools is a web based version and it would be current, not 2021. Are you actually using a cracked versionof SketchUp? What operating system? 2021 is not an operating system. What graphics card? 4GB is not a graphics card.

Where have you been saving the file while working on it?

Upload it to DropBox or We Transfer and share the link.