I've had the same issue, the fix was to perform a factory reset. there's one thing you can do is clear cache and see if it works before the factory reset.
Please try clearing cache of the device to see if it helps. As a work-around please try enabling air plane mode and disabling airplane mode to see if it helps temporarily resolve the issue. If you are on ZTI7 software, please update to latest software ZTJ3. If issue happens on ZTJ3, as well, please send us an error report immediately after issue is observed with a video recording if possible. Are you observing any loss of mobile data once this happens?
I tried clearing my cache in the app settings and in the recovery mode / bootloader after restarting my phone. Did not help. Tried airplane mode as you asked no different. I am on ZTJA update. Not sure about the version differences. I submitted an error report and recorded my screen using the screen recorder in the screenshot section of the error reporting. Also it should be more obvious that you can record your screen in the screenshot option. I tried to use the built in Samsung screen recorder but you can only attach images.
Hopefully the information I sent helps.
Again wifi works fine. Data works fine.
I cannot enter the wifi screen in the settings. That's the issue.
