Something weird has happened since the last HA Core and better-thermostat-ui-card updates. First my water heater card now displays 'configuration error.' There seems to be some confusion with the better-thermostat core version and the ui-card version. When all of the better thermostat cards are deleted from HA the one that appears as better-thermostat-climate card, produces a yaml type: custom:better-thermostat-normal-climate-card. This works but is missing some of the features previously available in the ui-card version. When the ui-card version is added back into HACS, it does not appear as a different card.
My original card has - type: custom:better-thermostat-ui-card and this no longer seems to be available.
To make matters worse, my water heater definition randomly changes domains. Sometimes it's climate.water_heater but then water_heater.water_heater. The better thermostat card only accepts climate domain entities so that alternately I can display the water heater, then not.
I had this same/similar issue recently where it was displaying "configuration error" because the card type was now wrong. Thus thank you for helping get it at least working again with the new card type as I use it in a pretty basic form.
There's a very nice documentation site, but unfortunately it's entirely setup to configure it through the HA interface. I use YAML and there are no examples of the YAML code as most sites include.