Typically for an issue like this, as it’s motherboard related apple will replace the whole device. You would have to seek out a third-party that specialises in microsoldering to fix the issue.

From a comment, the loop disease begins :( to continue using your phone for calls, you may have to resort to Bluetooth headphones if you want to utilise a mic. You can try to use lightning headphones but there is a chance that audio will continue to play out of your phone (depending on the stage of your loop disease).