I believe you'll find that KoReader needs an update to identify the Clara BW (P365) model. There looks to be code present within
koreader/frontend/device/kobo/device.lua that retrieves the devices codename from either the
environment or
/bin/kobo_config.sh and the product id from either the
environment or
/mnt/onboard/.kobo/version.
More than likely these will need to be updated. I'd suggest taking this discussion to either the KOReader forum or opening a bug report.
In fact I think there is an existing bug report. See
https://github.com/koreader/koreader/issues/13644