Hello dear colleagues.
Yesterday I updated a Drupal 8 site to 5.35.1. Afterwards many of menu URLs become replaced/injected with a "civicrm/a/#" string, for example domain.tld/civicrm/a/#/mailing/new or domain.tld/civicrm/a#/status; and the UI returns a blank page, not a white screen, but a page with no CiviCRM body content (see attached image).
Once this occurs the CiviCRM menu system is no longer active (clicking on any other CiviCRM menu does nothing).
I have also now done a net new composer based install (new o/s path and new DB) this time on Drupal 9 CiviCRM 5.35.1, and precisely the same problem occurs.
This is a CPanel Centos VPS server.
Your kind help is most appreciated.