I need a simple way to...

I have a A7RV and A7IV and want to show folks I'm shooting their photo(s) on an external screen as I go. In other words, I take a photo and they see it (on an external monitor) if I hit the Play button on the back of the body - just like I would if I were reviewing the photo myself on the rear screen. Would an external monitor connected via HDMI to the camera do this?

Do I need to check/change any particular settings?

Does it require I go through a computer?

Do I need any special cable(s) or other gear?

How long a cable can I use from the camera body to the monitor?

I think I'm looking to mirror the rear camera screen to an external monitor. I want to do this in the simplest way possible. Is this a simple thing to do? THANKS!