Hi there,
Mainly the TEN years , have you put the numbers in the online battery life sizer?
Xiao nRF52840 is plenty Powerful enough. That’s not a concern, nothing in the scenario you provide is outside the realm of the chip.
There is no way I know of or have seen to be able to turn on a BLE receiver via the remote BLE radio. That being said you could just advertise a beacon or some such when the IO is dictating it (broadcasting if you will the data).
Typically You would start at the Sensor Node and work backwards.
The Heartbeat is good for keep alive status, adding a watchdog timer if logic goes off-line.
We had similar WIRED life Safety in the FAB’s in OR. built into the SCADA systems monitoring hydrogen and other UHP gases to a master display.
HTH
GL 
PJ
PS.
you could institute Deep sleep and via RTC wakeup interrupt and have pre determines times & date window for system to come on-line and transmit (+/- some drift time) or connect to a central or master. The RTC batteries are closer to lasting years BTW, so that would be one approach you could take.