climate.xyz HVAC mode auto is not supported by this device, is it possible that you forgot to set the heat auto swapped option?

[ovizii]

Do I trust BT in this case or the developer tools?

Checking the developer tools shows a different result for the TRV. Siterwell GS361A-H04

hvac_modes:
  - "off"
  - auto
  - heat
min_temp: 5
max_temp: 30
target_temp_step: 0.5
current_temperature: 24.9
temperature: 24.5
friendly_name: ThermoBed
supported_features: 385