Actually, the biggest screenshot of the two was the end of the output of the "guix pull" command after doing the "guix gc -D" command.
And the "build --repair" command resulted in this output:
guix build: error: error parsing derivation `/gnu/store/8ablj2a1ihn32ilnfw1c3brpv9l7akzc-guile-json-4.0.1.drv': expected string `Derive(['
So, that file was empty as well: /gnu/store/8ablj2a1ihn32ilnfw1c3brpv9l7akzc-guile-json-4.0.1.drv
So I ran the "guix gc -D" on it, then "guix pull" again, and it found other empty .drv's. I repeated this scheme until the "guix pull" command was successful.
Thank you people so very much for your kind help!
My system is now bug free again. I don't know if I discovered real bugs, or if my system crashing twice during a pull command somehow broke it, but I hope this feedback helped. Maybe one day I will find out why my system crashed and rebooted by itself a minute later. After all, it could have been caused by something else on my system at that moment…
Have a good day! =)