iPhone 6S touchscreen and buttons not working

Hi, I have an iPhone 6S and starting with the iOS 12 update the phone has been locking up a lot. The catch is, the screen is updating but no touchscreen working whatsoever and the buttons all stop working too, including the silence switch. Headphone jack dies but charger sometimes fixes the issues altogether. We can use Hey Siri but it's not the most useful thing in the world when it comes to trying to tell Siri to restart the phone. After about 10-15 minutes the phone returns to a normal state but it's quite annoying and the screen has been replaced twice with this issue and nothing changed.

Now, the phone is a refurbish from Asurion but I'm almost certain it has no warranty, just looking for at home remedies for this if there are any, otherwise I'm just gonna stick to my iPhone SE. Thanks.