Adobe Acrobat Pro DC: Slow to open, slow to advance pages, slow to search

I get a spinning beach ball under the following conditions:

• Opening a PDF.
• Scrolling or clicking to advance a page.
• Opening the search box and conducting a search.

I'm ultimately able to open/advance/search, but the hanging lasts anywhere between 1 and 15 seconds.

My Adobe software is up to date.

I'm on a MacBook Pro running Mojave, 10.14.6.

These problems started somewhere around last November and have not improved.

It doesn't seem to matter where the file itself is located (e.g., deskstop, AEM DAM) or how the PDF was generated (e.g., Word, via InDesign). All have the same issue. Even small files (< 1 MB) give me problems.

Disabling Enhanced Security does not improve performance. Disabling Show Online Storage when opening (or saving) files does not improve performance.