Waiting time in Indesign

What I experienced what can slow down InDesign:

1. Preflight on >> Turn it off
2. To many fonts >> Reduce active Fonts
3. Cloud Services, like Drop Box >> Stop synchronizing as long as you work, for me it helped to download the app again and install it. I let run sychronisation when I was not using the computer and after that it was speeded up.
4. Work with Object Styles. During Work turn off balnced coölumns, at the end turn it on again.
5. Turn off creating previews for all pages. If it is on, after every change InDesign is trying to update the preview.

The bigger question is where do your files reside? Are these stored locally or are they on a network/external drive or cloud service like Google or Dropbox?

Some other things you can try:

1. Save your document using 'Save As' (not 'Save'). That'll delete the undo history and can shave off many megabytes from your document size.

2. Check whether there are many nested styles in your document. Especially nested GREP styles can slow down a document's performance.

You probably need to explore  resetting preferences . This guide shows there are several progressively deeper ways to reset preferences. One of them should work for you.

How much spare hard disk capacity do you have?
Have you tried resetting the InDesign preferences back to the factory defaults?