Error accessing files on Docker (Synology) library

Just set up a new yacreaderlibrary library using Docker. I'm able to browse the library, but when I click through to 'read' a file, it simply presents the metadata. I looked at the server logs, and these errors were present:

WARN 2022-01-12T02:27:45.113 Template: missing variable {page} in folder
WARN 2022-01-12T02:27:45.113 Template: missing variable {pages} in folder

These errors are generated each time I attempt to access a file.

Additionally, the following errors are sometimes generated:

WARN 2022-01-12T02:40:32.707 QObject: Cannot create children for a parent that is in a different thread.
(Parent is RequestMapper(0x56164277df60), parent's thread is QThread(0x56164277d7e0), current thread is QThread(0x56164277ed20)
! _7z.c:200: 7z support requires 7z SDK (define HAVE_7Z)

Just wondering if there are any other dependencies I should be installing that weren't installed when yacreaderlibrary was added, or if there are other tweaks I can make to enable file access.

You can't use that browser for reading. That's the legacy browser used by the iOS app years ago, it is there so people with old iOS devices can still use the server. To read remotely you need the iOS app.