@bennett-family, both RawTherapee and GIMP work just fine without an internet connection once they are downloaded and installed. You don’t have to pay monthly for Lightroom, you can pay $150 up-front and keep it for the rest of your life if you want to. 🙂 Keep in mind that eventually it will get old, and newer cameras won’t be supported over time. That being said, I purchased Lightroom 5 a couple of years ago, and never regretted it. It still works fine for me, and I will continue to use it till it doesn’t work for me any more!
One more thing. Affinity has Windows versions of their software as well! I own and use both Affinity Designer and Affinity Photo on Windows, and they work very well; I use them all the time. I have never used it as a photo editor per-se (I use LR for all editing) but it still comes in handy for removing backgrounds, cloning, and other stuff that people usually use Photoshop for. (I used to use GIMP for all of that stuff, till I got Affinity Photo.)