Hi Juangrullon96,
Welcome to the Apple Community, where some of us do our best to help each other.
Great work in trying to solve the issue.
Sorry you are still having such a problem with Keynote.
Wondering if your Mac has sufficient storage / memory for Keynote to operate smoothly.
You might want to check you have at least 50Gb free to work with.
Find out how much storage is available on your Mac,
How to free up storage space on your Mac:
https://support.apple.com/en-us/HT206996
If you do have plenty of storage / memory to work with:
You might want to try Apple Support's Suggestions:
If an app freezes or quits unexpectedly on Mac
https://support.apple.com/en-au/guide/mac-help/mchlp2579/mac
ALSO:
Sometimes third-party (non-Apple) apps interfere with the smooth operation of Mac.
If you have installed any third party apps recently, are you sure they are optimized to work with the Mac OS on your Mac.
Big Sur was a major update, and some older third-party apps are not optimised to work with it.
Eg: Apps may need to be updated to a compatible version or uninstalled.
(Safest way to uninstall is with an uninstaller from the App's developer.)
While working towards a solution ... if you need a keynote presentation urgently ... you might want to check out this article:
To open Keynote presentations in other apps, convert them in the Keynote app first:
or
Scroll down to Convert a Keynote presentation in Keynote for iCloud (if that works for you)
or
Scroll to the the bottom:
Formats you can convert Keynote presentations into
https://support.apple.com/en-us/HT202220
All the best :)
