@Stephen I've got (but have not yet installed) a bunch of old Sonoff devices (in-flush-box temp sensors & power switches, wifi & Zigbee), a couple unbranded 'Zigbee Smart Switch'es, and a couple Shelly 1PM Gen4s (to be used to switch on 16amp hot water cyclinder & car charging socket). With a local Zigbee hub, I don't think any 'cloud' service support is required.