New to the world of Ring Video Doorbells Help!

These may be simplistic questions but as I say, I'm new to this scene and couldn't find a "Newbie" forum! Having connected my "Wired Doorbell" temporarily in order to "see the view" from a couple of possible locations so that I know where I want it sited, I'm now waiting for my Glaziers to come and install the wiring in my UPVC door and screen, at the end of May, early June. This short time, of fairly intense use has depleted my Huawei P30 Pro phone's battery by 60% ! This is an enormous amount considering that my phone normally gets 3/4 days from a charge. Can anyone reassure me that once it is installed and the parameters "tuned" to my required areas of detection, the drain on my phone's battery will be negligible? Another thing which I don't understand concerns the "Cost" of answering the Video doorbell via the App whilst overseas as my 10GB contract allowance is barely enough for the duration of my holidays as it is! I have read somewhere that I can access the doorbell via a browser, ...is that any different? I suspect that using it this way would take so long that any caller would be long gone before I was able to greet them! Any clarity would be gratefully received. Thanks.