I got the "Pepper and Church" Salt & Sanctuary save editor working, but it's convoluted with many steps. Once you've done it a few times, though, you can recognize various areas and you can search for key words yourself.
The editor will not work with the "saveslot" file as presented by Checkpoint. To get it to work, you have to trim the config header from the file. Search for the character's name, and cut everything before the "1D" hex that you can see before the name.
Copy "saveslot" to the editor folder, or somewhere equally convenient.
Copy it to "saveslot.bak".
Copy it again to "saveslot-trimmed". Operate on this for the trimming part.
Before trimming:
After trimming:
Now, copy this file to "saveslot-saved". Open this file in the save editor:
Without changing anything, save it once. Close the editor. Copy the saved file to "savedata-savededited". Now open this file in the editor, and change your Salt value. Save, and close.
Now do a binary comparison between the "saved" and the "savededited" files. How? That's your problem.
The reason for saving first before changing anything is so that there will be fewer results in the comparison, as both files will be the same size. However, the editor still throws a few changes in the header which are irrelevant for our needs.
As you can see from the editor screenshot earlier, my Salt was at 600. In hex, that's 0x0258, which is "58 02" when viewed in a hex editor.
The value to the right is my gold, 4656.
Now go back to the original "saveslot" file, and search for your particular values. In my case, I would search for "58 02 00 00". Edit, send back to checkpoint, and enjoy.
Item quantities are much easier to find, but you must have at least one in your inventory and you must know the internal item name. This is for black pearls:
I now only play S&S on my legit switch - I can't access those saves without risking Nintendeath so I can't help out any further. Have fun, and remember to keep backups of your pre-edited backups.