I followed the instructions for setting up YAC Server on QNAP - and then ran the YAC create-library command, which was successful, however the following were reported many times (maybe 100-200 between all 3).

• ! _7z.c:200: 7z support requires 7z SDK (define HAVE_7Z)
• ! rar.c:214: RAR 5 format isn't supported
• ! rar.c:71: Splitting files isn't really supported

How can i add this support to my QNAP container/docker image?
I cant even tell which files are failing to re-encode them manually.

I have too many comics to manually go through and try to figure out which weren't imported.

Thoughts on the best way to handle this?

You need a build that uses p7zip instead of unarr if you need support for 7zip and rar5