I've worked in WordPress many years and never seen this particular behaviour. The white screen of death only shows on Post Publish or Update. It doesn't show on WooCommerce Category additions. It doesn't show on plugin additions, etc. The front side of the site shows just fine.
No PHP error shows with WP_DEBUG is set to true. It doesn't change when all the plugins are deactivated. The wp-config and .htaccess files seem to have the correct address settings.
When the back button and refresh are used, the changes show, so I think this is a redirect problem. It's just not redirecting to a confirmation page. What could be causing this problem?
New information: three of us were working on the site in a work meeting today, each of us has our own logins. Towards the end of the session, one person, who had entered 51 posts successfully, had the white screen of death on all dashboard addresses. But, two of us were successfully logged in and working. Now two of us have the white screen of death. The irregularity in the problem is puzzling.