Why is my screen black but still responsive to touch?

I haven't dropped my phone, had it near water, or cracked it. I haven't even had it a full year yet. I put it on charge last night and this morning the screen wouldn't come on. Last time I checked battery health was 86%. I have tried force restarting it and charging it. Phone is completely responsive to touch and I can do what I need to with Siri. I've seen conflicting answers on if it's a battery issue or screen issue, can someone help?