CORRECT SOLUTION:
1. Install official Microsoft Compatibility Administrator found here: https://docs.microsoft.com/en-us/windows-hardware/get-started/adk-install#adkwin10
2. start "Compatibility Administrator (64-bit).exe" in C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Windows Kits\Windows ADK\Application Compatibility Toolkit\Developer and Tester Tools\
3. expand "System Database" > expand "Applications" > find and click "adobe creative suit 6" > on the right window "right" click pdapp.exe "Disable Entry"
4. Run Acrobat XI Pro, now insted of crashing it will show a "new" adobe activation agreement (this is what was crashing the acrobat x pro), you can now accept it and Acrobat XI Pro runs with 0 issues in 2021. (no need for any compatibly modes).