Chosen Solution
Haven’t had an iPhone 8 with these symptoms. People can’t hear me clearly during phonecalls whether in handset or speakermode. Sounds like I am far away or voice is cut off so I sound like I’m stuttering. Using voice memo voice works perfectly. My colleague changed the charging dock and it was fine for a day and the problem returned. Audio IC related problem or something deeper perhaps. Any advice would be appreciated.
Can Siri understand you? If she can and as you said voice memos work fine I would be leaning towards a parts problem. When I am faced with similar problems I would put the logic board into a known good housing and screen. If it acted the same you know you have a board problem. I have not uncounted an iPhone 8 that needed an audio IC repair but anything is possible.
