Chosen Solution
Bought the full display assembly replacement part and swapped it onto an iPhone SE. Everything works except for the speakerphone microphone (the call microphone works). Any connections I should double check? Or is this indicative of a faulty part?
The full display assembly comes with the small parts already installed. While a time-saver, small parts are themselves notorious for lower quality. It’s always best to transfer over the Apple original parts to the replacement screen. You already paid for them once, no point in throwing them away :>) I would transfer it over, following this guide to see if it solves your problem. If it does, you could reach out to iFixit to see what they can do.
