What channel/app are you using to view your local channels? You probably have to take it up with the provider of the channel/app. There isn't a Roku setting for your local channels. Most providers obtain your location via your public IP address which can change at any time depending on your ISP, but it is strange that you're getting different channels on different devices connected to the same network. My gut feeling is that eventually all your devices will be getting the same local channels.
One thing to try is to remove whatever channel/app you're using by highlighting it on the Home Screen and pressing * on your remote - choose Remove channel. Restart your stick from Settings->System->System restart <-- don't skip this step. Add the channel again from Streaming Channels.
Note that a channel/app that is removed from one device will be removed from all devices linked to the same Roku account, but it doesn't happen immediately, so your other devices should be unaffected.
There are several services that provide a location from an IP address and they don't all agree. One is https://www.iplocation.net/ . Try it and see where it says you're located.
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