Any reason the current Tools -> Autocorrect Options  'Replace' 'With' handling is not sufficient for this use?

Assignment of shortcuts is mostly limited to single UNO commands but Macros can be assigned. It also has limits as to the keyboard keys available to assign (bug 115052).

For this use case seems an string autocorrection rather than a single keyboard shortcut/accelerator is better choice and is already available to customize.

There is no reason at all why this is not sufficient! I simply didn't know about it. Thank you very much for letting me know!

It's worth nothing that this not what I'm used to doing, coming to LibreOffice from other word processing software where there was the option to assign shortcuts to special characters and symbols. In addition, when I searched for information on how to do this in LibreOffice, I didn't see this advice anywhere. 

In which case, can I recommend adding it to the existing literature? I didn't see it when I was looking through, but that doesn't mean I didn't just miss it. If it's already there, it might need to be amended to include SEO (dunno if that's how you phrase that) for 'special characters' and 'symbols', maybe even 'keyboard shortcuts'.

As an aside: as it is a common feature on other word processors to assign shortcuts to symbols, perhaps consider this in the future for useability? Though not as dire as I thought it was (sorry about that!), it may make the software even easier to change over to. The autocorrect feature doesn't, after all, allow alt/ctrl commands, which some people may prefer.

Again, thank you very much for your help!

Agree the documentation can be a little obscure. Guess it could use some attention in Wiki, Getting Started or the module guides.

Here's a Google AI Mode response to the query "for libreoffice correction strings should i use autocorrect simple text replacement or a full macro assigned to a text string"

<quote>
For simple text replacements (like typing (c) to get © or a typo correction), use LibreOffice's built-in AutoCorrect; for complex actions (like inserting formatted boilerplate or conditional text), use AutoText (easier than macros) or a Macro for advanced logic, but AutoCorrect is best for quick, automatic fixes, while AutoText/macros handle larger, multi-step insertions. 

Use AutoCorrect for:
Typo Fixing: Automatically changing common misspellings (e.g., teh to the).
Symbol Insertion: Replacing short codes with symbols (e.g., (c) to ©).
Simple Text Expansion: Replacing a short string with a longer one (e.g., addr to your address).
Quick & Seamless: Works instantly as you type, ideal for frequent, small corrections. 

Use AutoText for:
Boilerplate Text: Inserting entire paragraphs, addresses, or formatted blocks.
Reusable Content: Store common phrases, tables, or even headers/footers.
Faster Insertion: Type a few characters and press F3 (or Enter) to expand. 

Use Macros for:
Complex Logic: Performing multiple steps, conditional formatting, or data manipulation.
Advanced Formatting: Applying specific character or paragraph styles with precision.

Custom Functions: When AutoCorrect/AutoText can't handle the required actions. 

How to access in LibreOffice:
  AutoCorrect: Tools > AutoCorrect > AutoCorrect Options.
  AutoText: Tools > AutoCorrect > AutoText or press F3 after typing the trigger. 

Recommendation: Start with AutoCorrect for basic fixes. If you need to insert formatted blocks, use AutoText. Reserve Macros for truly complex, custom automation.

</quote>