RegEx to Match Sentence -- Works in RegEx101.com but not KM

Bingo! :+1:
I can't believe I made such a rookie mistake. :blush:
The RegEx and macro now work perfectly.

I have made some minor updates to the RegEx:
RegEx101.com Extract Sentence from Paragraph
([A-Z].+?(?=(?:[\.?!]\h+[A-Z])|[\.?!]$)[\.?!])

Thanks again @mrpasini.

Here's my finished Macro for Pages based on this:
MACRO: Pages -- Select Sentence [Example]