Zigbee radiator valve (TRV) on external power supply

Most of the available sensors as well as radiator valves work on batteries. This is something I like to avoid, there is always something not working because one of the many batteries requires replacement.

Now about the radiator valves, I have several radiators which are placed behind a ‘panel’ or at a location where it is not easy to replace a battery.
A wall outlet near a radiator is never a problem, so I was planning to us a USB power supply and a 3V step down converter to power the radiator valve.

I initially bough a Tuya, however it turns out, that after a power outage, the button must be pressed twice (calibration ?) before it starts working. This makes the external power supply rather useless.

Another option might be a Sonoff TRVZB. I do not want to buy this as well; it might have the same ‘feature’. Anynone here who has and knows the behaviour after
the batteries are replaced. Does it require button presses as well ?

Anyone else who did (or wants something similar) with a TRV ?

I was not planning to use the valve for autonomous temperature control. Like to have the temperature reading and be able to open or close it.

Some other options I have in mind:

  1. Leave rechargable batteries in and trickle charge with a current source and a few mA. This is safe for the batteries and would keep them charged.
  2. Use a mains powered thermal radiator valve and something to control it (e.g. wall socket)

Any other ideas ? or sugegstions for other valve. Preferably Zigbee, Tasmota would be fine as well.