I have deCONZ / ConBee2-GW dongle and Aqara temperature and humidity sensors.
What I have noticed is that after a restart/reboot of HA it takes a long time (20-30 min) before I get temperatures shown in HA.
Why is it taking so long time … is it a deCONZ problem?
If so … is there a better alternative to deCONZ?
These are low power devices, that broadcast their sensors values only once in a while - when there is a change of value or triggered by some internal timer. So it is perfectly normal behaviour designed to save battery.
You should retain values on HA core restart, as deconz will continue to run and report values in another container (assuming you use deconz add-on). Restart of host will cause also restart of deconz and it will require some time to gather values from all sensors, but this is sensor triggered process, not HA or deconz.
OK … good to hear that is a normal behavior