Subfolders of shared mailboxes are not displayed when using Client V.10.4.5674 with EWS protocol on Windows 11.
Instead shared folders are fully displayed using the IMAP protocol.
Additional note:
The same applies to calendars, contacts, and resources in EWS.
In EWS, only the shared default instance is displayed for subscribers; additional shared sibling or child instances are not shown.
In contrast, when using the CalDAV and CardDAV protocols, everything is displayed in full.