On 'Reinstalling Keynote' after accidental deletion: recommend noting to people that they will have a chance to download the older version. MEF
More than 85 people had this question, and all recommendations indicated they should (buy and) install the new Keynote; it may be a wonderful software, but the user community should know that they can also download and use the old one, without further purchase.
MEF, Virginia, nine-year Apple user and software developer
MacBook Air 13″, macOS 12.7