I know it’s a lot to keep up with, but I never said that all hardwired zigbee devices are repeaters. I said most are, but it’s up to the individual manufacturer. And I gave as an example Smoke alarms, which typically are not repeaters, and also the Sengled element bulbs.
With zigbee, the only way to be absolutely sure is to contact the manufacturer and ask. Or, as @GavinCampbell Suggested, you can buy an additional device and map your zigbee network.
With Z wave, you can look up the official conformance statement for any certified device: