I came to a different conclusion and solution for this error and wanted to share my experience in case it helps. If it sends anyone on a wild goose chase, my apologies up front.
My Shortcut Logic was good.
The Mac OS error I encountered was "Could not find the shortcut “Open Today’s Note.”
When I opened the Shortcuts app on my Mac, there it was… Open Today's Note.
When I played the Shortcut from that app, it actually opened the right Note.
The problem wasn't in the logic of the shortcut (e.g., 'Find Note' vs. 'Open Note').
The Link to the Shortcut is the issue.
Back in a #ForeverNote, I edited the link to "Today" and saw the special characters representing spaces and the apostrophe or right single quote in the Shortcut name (Open Today**'s** Note = Open%20Today**%E2%80%99**s%20Note)
URL encoding substitutes ACII characters for spaces, puncutation, etc.
The trouble seems to be that different character mappings are applied and used in different places.
%27: This is the standard URL-encoded ASCII character for a basic single quote or apostrophe.
%E2%80%99: This is the UTF-8 hexadecimal sequence for a typographer's "smart" apostrophe or right single quotation mark (’).
The shortcuts I had in Notes all used the UTF-8 character mapping …%E2%80%99
Mac OS now seems to want the standard URL ASCII encoding … %27
The Fix(es) - you have a choice
Assuming your Shortcut, Open Today's Note, works independently of any links to it…
You can leave it as is and globally update the links to it from:
shortcuts://run-shortcut?name=Open%20Today**%E2%80%99s**%20Note
to
shortcuts://run-shortcut?name=Open%20Today**%27**s%20Note
You can take the extra steps of renaming your Shortcut to remove the apostrophe AND update the link globally.
Open Today's Note becomes Open Todays Note
The link update globally looks like …
Before: shortcuts://run-shortcut?name=Open%20Today**%E2%80%99s**%20Note
After: shortcuts://run-shortcut?name=Open%20Todays%20Note