Look for the active location indicator that I described in a couple of posts above.
This little symbol says something is using GPS. But as you say, unless the app asks to use your location, you may not know that it is. A good example is the Camera app. Otherwise, trial and error by "killing" the apps one at a time is the only way to know. And if you have multiple apps that are involved, unless you systematically open and close them individually, you may not be aware of all of the culprits, so to speak.
On a Mac since 1984.
Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.
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