Power button not working

I have an iPhone 7 that has a power button that is not working. The volume works fine. The phone is up to date 11.2.1 and the power button is not loose or physically damaged. The phone has never been repaired. I tried restarting the phone by using assistive touch, but the phone goes into a boot loop until I plug in the charge cable. There is a warranty on it, but I find these symptoms very odd. Outside of restoring it to factory settings, does anyone have any tips or tricks?