Yes, you can play 4K videos on iPhone 8.
No. iPhone 8 does not have the FM radio.
Yes, iPhone 8 does have Dolby Digital & Noise Cancellation.
Though Apple never mentioned the battery capacity on their website, during our review of the device we found that iPhone 8 does have 1821 mAh Li-Ion battery.
No longer the gold standard, the iPhone 8 is still all the phone you need.