So, this happened to me too, and as you suggest, I took it in to apple....I was chatting good night with my daughter who was lying in her bed, phone in her hand (I caught her still, up, texting...) and while I was talking to her, her iPhone 8 died as in the screen went blank. Then as none of the buttons were working, she handed it to me. We turn on the light and her home button was cracked. There is NO way she wouldn't have noticed this earlier on her "precious" and she did not drop the phone in the last two months (brand new in December, and yes she did damage the glass screen saver one time in the first week she had it). Even if she had, it was in a case, with a protruding front lip. You'd have to hit this with a nail and hammer to get a crack right on the home button....
So, I found out we have a $150 deductible with the carrier's insurance. So then I chatted with an apple agent for 96 minutes, rebooting (unsuccessful) and then restoring the phone to discover, of course, that the home button didn't work. So then we went to the store. They went through the same process, and then insisted that she must have dropped it or it wouldn't have cracked. I agree it is hard to believe, but I was there.... she didn't cause this! They apparently think we are lying. So, $169 later (they told me $149, but of course then you pay tax too, which was left off the discussion...), another hour and half (took longer than they said to fix, which also makes me wonder), she has functioning phone again, but I have had it with apple. I have had all apple stuff for years and happily bought an 8 plus when we got her the 8, but I will not be buying any more apple gear, and now I am just waiting for my home button to crack too.... Last night, I had read some of the posts on this website. How could all these people have spontaneously cracking home buttons on their iPhone 8s without there being some fault with the phone? I am really, really disappointed.... and angry that I have wasted all of my day off plus a substantial sum to get it working again. What choice do you have at that point?
I welcome a response from Apple, and I'll be waiting for them to own up to this fault and issue a refund, but I don't know how they can win back my enthusiasm.