I'm so sorry for the delay, Turned out I had a backup on my External Hard Drive (how could I even forget) so I could get it back pretty easily.
However, for the sake of the "bug" resolution I'm going to try to add info.
There was indeed probably a good file in the .autosave folder but I had deleted it a few days prior when I was sure my substance was finished.
I do not have the original "bugged" file anymore, but I have an autosave of it and it also has no graph, exactely like the original file. I would gladly send it, but I can't attach it here because apparently .sbs files are not supported (as shown on the screenshot). If you have a workaround, I'll gladly sent that autosave file - if it's even useful since it's not the original.