I’ve been using Lovelace for a while,
Used customs cards as well, but since moving to the last Lovelace version (storage saved and no yaml) it feels like some great functionality was lost.
Custom cards are not supporting on screen editing apparently, and the ability to style on / off look for buttons that are not switch component based (light / input-Boolean / group / automation components) is not possible using the button-entity card as far as I see…
Is there a way (using style or other configuration method) to achieve this?
Am I using custom card correctly? (Should I be able to do on screen editing?)
I’m sorry but that’s just false. You can either use YAML mode - exactly the same as before OR you can use the raw editor and edit the YAML. You have lost exactly ZERO functionality and gained a lot with the graphical editor.
As regards your question, this is why a lot of people use the custom-button-card.
The functionality of the core button card is a reflection of the philosophy of the devs and how states can be shown and what can be shown. It’s a pity but that’s why there are custom cards.