Chosen Solution
This is not afaik the apple logo loop, the phone works normally for a few minutes and then shuts off in the middle of whatever I happen to be doing. About a week after the warranty was up, the microphone stopped working, and I could only use the phone with a headset, but otherwise the phone worked normally until now. The battery reads full. I have restarted the phone, I have done a reset, and I have done a full backup and DFU and reinstalled everything. My theory is that the charging port and microphone are so close together that somehow damage occurred to both. This first buggered the microphone and is not maybe shorting things out? Not sure how to proceed. I have never previously had a problem with any apple product, so this time I decided not to buy apple care. the apple store wanted 600$ to look at mic, and said if there was evidence of water damage it would be unfixable. AFAIK it has not gotten wet.
Apple will say that it is water damaged as they are not allowed to replace the charge port. The only thing they can replace is the screen and battery anything else is a refurbished phone. Replace the charge port assembly. Make sure you purchase from a reputable parts store and not eBay or amazon. I try and find a seller who offers pulled ones from original phones. Once replaced as long as your battery is good your phone should function properly.
