There are a number of ways of achieving what the OP seeks to do, but in my opinion, the simplest way with the least amount of work is to copy or backup one file, after you have added shortcuts, and that is -
This is a binary file, not a text file, and so its content cannot be easily read unless an intermediary method is used (such as dconf-editor).
The tilde ~ is short for
So for me, that would be
The dot before config indicates a hidden file or folder, in this case, a folder.
To see these in your File Manager (Nautilus aka Files, under GNOME), you can either toggle their appearance and disappearance with the use of
or set the preferences to show hidden files and folders if your FM's preferences accommodate same.
So if you incorporate the saving, backing up, or snapshotting (the latter with eg Timeshift for EXT4 or Snapper for BTRFS) to include that file, you can preserve your Custom Keyboard Shortucts as well as other settings.
The use of a GUI settings editor such as dconf-editor
sudo dnf install dconf-editor
will allow you to see the hierarchical structure of how settings are stored, and the content, such as
(and to change same)
The use of the commands
dconf and gsettings
can also allow you to get, set and dump settings content in a user-friendly format, including text files that can be stored any way you like.
If you have need of further elaboration, just ask.