Why can't i instantly access the flashlight on my Xr phone?

That’s because you are swiping up from the bottom. For an Xr you open the control center by swiping down from the top right corner of the screen.

You can also turn on the flashlight from the lock screen by holding your finger on the flashlight button until you feel haptic feedback (1-2 seconds), then releasing it.

The flashlight icon is at the bottom left on the lock screen on my XR. Tap and hold it briefly to turn it on and off.

Control Center. Swipe up from the very bottom of the screen

If not there, visit Settings / Control Center / Customize and make sure the Flashlight is in the Included section.

If the Control Center does not come up on the locked screen, enable that in Settings / Face ID & Passcode, in the Allow Access When Locked section.

Well, it shouldn’t. There’s a slight chance that your RAM (not storage) is too fragmented for the camera to load. You should restart the phone if this happens—>Restart your iPhone - Apple Support. It’s important to do it by shutting down, then restarting, rather that a forced restart (Volume Up, Volume down, hold the side button) because a forced restart does not give apps a chance to save their data before shutting down. It’s a good idea to restart your phone periodically (perhaps once a week) because while it’s called an iPhone in reality it is a very powerful pocket-sized computer that can also make phone calls. And all computers need to be rebooted periodically.

If it happens soon after restarting your phone may have a hardware problem.