Thank you for reaching out, and sorry about the trouble caused.
As you mentioned, the editing tool is working very slowly. Please let us know if this happens with a particular file. Is it a large file? Try opening a small file and check if you experience the same behavior.
Try repairing the application and check if the application is updated to the latest version. In Acrobat, go to File > Help > Repair Installation.
If that does not help, try reinstalling the Acrobat using the steps suggested below: