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You somehow activated the Voice Assistant mode of your phone. When it is enabled, you have to tap on item to select it first (make sure the item has blue/colored outline) and then double tap on it to open that item with that outline.
To scroll or swipe you have to use two fingers. Scrolling or swiping with one finger will not work.
Hit the menu button or open Apps list screen. If you have screen locked, then swipe with two fingers. If it asks for PIN, then touch the first number and double tap it to register it. Do the same for remaining numbers to unlock it. Or unlock with Finger print
Then tap and double tap on Settings. Remember, When Voice assistant mode is enabled, double tap work as single tap.
You have to use two finger to swipe up or scroll down. Scroll down with two fingers, open Accessibility (tap it and tap twice on it to open), tap and double tap on Vision and then turn off Voice Assistant from there (tap and double tap on Voice Assistant switch).
Please let me know if that didn't work, so we can continue troubleshooting.
See this Youtube video. It shows how to enable/disable voice assistant--> https://www.youtube.com/watch?v=6Xh1iqOqwOk
If your phone is completely frozen and not responding to any touches or swipes with two fingers, then you can force restart it. To force restart, hold down Volume Down and Power button until it restart and shows Samsung. Only do this if the above steps are not working. When you restart the phone, it will ask for passcode or backup pin you setup with it. If you don't know it, then then do not force restart it