Go to "Integrations" → "AgentDVR"
Add URL, no #Best option I found was to have camera on it's own lovelace view w/ "panel" mode and then the alarm panel on another screen. This allows using "browser_mod" to work best by opening that URL. I haven't figured out how to automate opening fullscreen, but it's better then ZoneMinder in a way because the stream in HA is live always.
Here is an example LoveLace UI. The difference between iframe/webpage/picture-entity is "iframe/webpage" is Live, but it's like embedding a web browser, you can't interact w/ it like iframe/automations via "browser_mod". Try both and see what you think.
type: vertical-stack cards: - type: alarm-panel states: - arm_home - arm_away entity: alarm_control_panel.agent_alarm_panel - type: picture-entity entity: camera.name camera_image: camera.name - type: iframe url: 'https://domain.com/' aspect_ratio: 100% - type: entities entities: - entity: camera.name