Iphone 8 plus stuck in boot re loop?

I have had my iphone 8 for about 2 months now and recently it has started randomly getting stuck in a boot re loop, it'll happen randomly during the day. It'll be fine one moment then the screen turns black and the apple logo appears, the screen will go black for a second and i see a thin green line and this happens for sometimes 30 mins to an hour. I tried force restarting but it doesn't work! Someone help!

Apple iPhone Upgrade Program?

When I sign up for the iPhone upgrade program through Apple, I'm paying that $40 or so to Apple every month, but is that IN ADDITION to what I'm paying my carrier for my service? Or is this just an alternative payment method?

Instagram Can't Login on my iPhone?

I've tried everything, I've updated everything, I've done the restart by holding down the home and top corner button, I've also deleted the app and downloaded it again. I logged onto the help center which said to change your password and if that still didn't work to change your password again, alas I stand before you having changed my password 5 times. I can't "report a problem" on my computer because the settings doesn't have a report my problem! Someone please help!

Can you disable passcodes and Face ID on the iPhone X?

I have an upgrade available and thought about getting the IPhone X. However, on any iPhones I've had, I never used a passcode or Touch ID. I don't use Apple Pay or the wallet and not really keep much personal info on there. Anything I do have is a few banking apps which have their own passwords.
Anybody know if I can use the phone without having to set up a passcode or Face ID?