Have you updated your Shelly Gen4 device to the latest v2.x.x firmware?
The original firmware many Gen4 devices shipped with (v1.9.x) had various Zigbee issues. The Zigbee part of the firmware seemed to be not yet mature enough. My Gen4 devices were basically unusable with that firmware in Zigbee mode (see also my earlier post on my observations).
I switched to WiFi/LAN mode and connected them to Homey via that route, similar like my older gen Shelly devices. The added value is that, in WiFi/LAN mode, the Shelly Control app exposes more sensors/capabilities to Homey then in Zigbee mode.
