Premiere 2023 *very* sluggish with simple still images (.jpg)

UPDATE #3:  Re-setting and restoring Premiere preferences *seems* to have fixed this behavior... hope this helps someone!

Delete the Media Cache and Media Cache files:
https://community.adobe.com/t5/premiere-pro/faq-how-to-clear-your-media-cache-in-30-seconds-in-premiere-pro-2020/m-p/11017257/thread-id/260446?page=1

If that doesn't work, try resetting the preferences:
https://community.adobe.com/t5/premiere-pro/faq-how-to-reset-trash-preferences-in-premiere-pro/td-p/8236158?page=1

If that doesn't work, try resetting the Workspaces:
Reset a workspace
Reset the current workspace to return to its original, saved layout of panels.
1. Do one of the following:
• Click the Workspace menu icon and select Reset to Saved Layout.
• Choose Window > Workspace > Reset to Saved Layout.
from here:
https://helpx.adobe.com/premiere-pro/using/workspaces.html

If that doesn't work, try creating a new project and import the old one into it.

UPDATE #2:  The variable seems to be number of stills in the timeline.  The affected timeline is roughly 17:00 long, with maybe 50 stills.  Every still is very sluggish to move *unless* I delete all other stills in timeline... then it's very zippy!  Why?  This has never been a problem before, and I have plenty of RAM dedicated to Premiere.... Anyone at Adobe have any ideas?  Thanks in advance.

Update:  Appears that trying to move anything in Program Monitor (stills or video, but stills are worse) brings the beach ball... changing numbers in Effects Control is a little better, but still not good.