How do you change the shell theme? I’m having trouble doing so, any help would be much appreciated.
Install the user theme extension from https://extensions.gnome.org/
You can enable via the gnome-tweak-tool or via the about page on the above site.
You must be clairvoyant to the extreme. I do not even understand what the OP is talking abouit. No openSUSE level, no mentioning of what desktop, no mentioning of what shell (ksh, bash, POSIX, …).
I guess this will be one of the more ununderstandable threads in the future (if not now).