@wild_bloody_roseThe only thing that we didn't try was to reinstall the game itself. Unfortunately, It is time-consuming work. This will not eliminate your saves or library, but in order to be on the safe side, move the whole folder of the game to the desktop.
After switching on the game when a new folder has been created, you will copy the Tray and "saves" folders into it - nothing more. To do the same with mods folder will come time after checking if you can connect to the Gallery.
The other thing is if you have two running antivirus programs - Windows Defender which you got with the Win10 system and some other one.
Windows Defender can nicely block some Origin files.
If even this way does not help, the only cause can be some other program running in the background connected to the Internet, which interferes with your connection to the Gallery.