Thanks for catching that. The System Spell Check (which is what you'd use if you don't have Spell Catcher) is on top now (with A as the Hot Key)/ The [SC] label indicates Spell Catcher.
Spell Catcher is 32 bit, as I recall, so it won't survive an upgrade beyond 10.14 Mojave.
Every now and then, I think of trying an alternative to the system approach.
FYI, I'm working on Literary Toolbox III, which is a streamlined version of the current release (omitting the 32-bit software and reassigning hot keys):
At the same time, I've been working on *Text Toolbox I, a companion toolbox to alter text for publication that mimics what Spell Catcher's Modify menu used to provide on systems before macOS Catalina:
If you have suggestions for either of these or would like to test them, just let me know.