Keynote Version for Big Sur V11
Where can I find the keynote version for my older operating system?
Mac Pro (2019)
Question marked as
If you ever installed Keynote from the Mac App Store previously (since Oct 2013), you can sign into the Mac App Store using the identical Apple ID. Press cmd+0 (zero) to open the Purchases panel and locate Keynote. If there is a blue cloud icon with a down arrow, or just an install button, click that and do not click Cancel on any subsequent dialogs. It will install Keynote v11.1 on Big Sur for you.
If Keynote was preinstalled by Apple or you never installed it via the Mac App Store then there will be no installation available to you. You will need to resort to using Keynote for iCloud.