Sigh … after an hour of prodding, I’ve discovered Raspberrypi 4B is a 32 bit system.
It appears that all Inkscape releases since 0.92 (2019) are for 64 bit systems.
The Inkscape 0.92 Preferences for “Interface” doesn’t have origin selection. This was added in version 1.0
Using old 0.92 version also explains why I’ve been confused using current documentation.