Lovelace - customize card and more-info

Hi guys.
I’m not into frontend development, so I need your assistance.
I want to do 2 simple things:

  1. Modify the original lovelace thermostat card so it allows me to set custom operation mode.
  2. Change the more info dialog of the PTZ camera, so that clicking on the image edges rotates the camera

ad.1. I’ve tried to move src/panels/lovelace/cards/hui-thermostat-card.ts to ~/config/www/ directory however it won’t work, as hui-thermostat-card.ts is using some imports with relative paths… How can I easily modify the card so I can use another operation_mode? It would even work if instead of ‘Heat’ operation_mode I could use my custom mode.

ad.2. I’ve tried some time ago with creating ~/config/www/custom_ui/more-info-onvif.html and giving it the same content as the original camera more-info panel, however it was not working. How to make it with lovelace?

Am I the only one thinking that frontend dev documentation is missing many important topics?