Can't manipulate large page size PDFs anymore (in Acrobat 9.3), Help!

Long time user and owner of Acrobat 9.3  I am an architect and product large PDF files (30x42” sheet size) and combine into multi page documents. After a recent ‘update the security settings’ request from Adobe or a Windows 11 update, I can no longer manipulate PDFs that I have exported from AutoCAD (2004).  The files open and then crash the second I initiate a command such as rotate.

Any ideas? Unwind an update? Re-install Acrobat?  Something simpler?  

Help!