@xpspiq wrote:
We are considering purchasing an ORBI modem and add an Outdoor Orbi Extender to provide wifi to a building ~250 feet away.
An Orbi RBS50Y is indeed rated for "outdoor" use, but is unlikely to solve the problem. That distance is simply too far for an ordinary WiFi access point to provide a strong signal, particularly if it has to penetrate the building wall in addition to the distance.
How to provide WiFi to a separate building is a frequent question. The "A" option is to install a Cat6 ethernet cable between the buildings. A cable provides the highest connection rate and is totally impervious to trees, weather, etc. When this is impractical (as it often is), the "B" answer is to install a "point to point wireless bridge". Almost every manufacturer sells these. How about looking at the user reviews for products such as the Ubiquiti NanoStation: https://www.amazon.com/NanoStation-NS-5ACL-US-802-11ac-Airmax-Radio/dp/B07GPQKLXW/ref=sr_1_6?dchild=...
They make at least a dozen different models, some with higher throughput (some with less but maybe "enough").
Those product reviews will illustrate how others solved the issue and will most likely point toward similar products from other vendors.
There are some cool YouTube videos showing how to set up point-to-point bridges.
Since these gizmos are distance rated in terms of "kilometers", there is a good chance they can be deployed inside the main house and distant building.
Good Luck
