Voltage Drop Resistor (?) on a Wall Wort?

I could use a little help adding a power supply to a freshly installed Ring Video Doorbell 2. Right now it’s running on the supplied rechargeable battery and ‘ding dongs’ via a shared Chime Pro. There is no AC powered doorbell at this entry and I’d like to be able to maximize it’s performance without depleting the battery weekly. At issue: A lot of conflicting data on the use of wall warts. a) Ring Help: [https://support.ring.com/hc/en-us/articles/205180710-How-to-Connect-Your-Ring-Video-Doorbell-Directly-to-a-Low-Voltage-Transformer-Without-a-Pre-existing-Doorbell](https://support.ring.com/hc/en-us/articles/205180710-How-to-Connect-Your-Ring-Video-Doorbell-Directly-to-a-Low-Voltage-Transformer-Without-a-Pre-existing-Doorbell) (applies to both Ring Video and Ring Video Doorbell 2) states that you must splice in a 25 ohm / 50 watt series resistor. I can only think that the resistor in series with the Ring is to produce a voltage drop. If the Ring is also 25 ohms, the net of a 24V supply would be 12V to each. Is that closer to what we want?? Why start with a 24V transformer if we really want far less? b) Ring Sales: [https://shop.ring.com/collections/accessories/products/plug-in-adapter](https://shop.ring.com/collections/accessories/products/plug-in-adapter) for For Ring Video Doorbell, Video Doorbell 2 and Video Doorbell Pro. Tech specs: 24V @ 20VA (so almost an amp). Installation instructions? Just connect it to your product! No mention of a resistor needed or critical doorbell settings. Conflicts with "a". c) I see transformer listings on Amazon ranging from 16V/500mA all the way to 24V with a few amps – and each has hundreds of positive reviews stating they all work great. Ring’s instructions say the doorbell 2 works with 8 to 24V. Given that this is basically for charge maintenance and not primary power (and I assume we must have DC rectification and a good 6V max regulator in play to feed a Lithium battery, how much AC output do we really need?? On a lark (returnable to Amazon) I bought a Voyaux Power Supply Adapter. The box is plastered with Ring Doorbell product pictures and assurances that it works with them. It is spec'ed at 16V AC / 800mA. Can I get away with a smaller resistor, or no resistor? Are we closer to the doorbell's needs? d) Despite dire warnings not to use with DC power systems, I see there are various solar power kits available. Last I checked, photovoltaic cells had a DC output. I’m left confused…. Thanks!!