Don’t know about the charging issues, but the reason replacing the microphone didn’t help is because you replaced the wrong microphone.
iPhone 8 has 3 mics.
- One for regular phone calls - which is the one you replaced
- One for the front-facing camera - which is used for the speakerphone and FaceTime and is located near the earpiece
- One for the back-facing camera
“Up from the left” means lift up the left side.
Which is the same as folding to the right.
“Like the back cover of a book” explains it even more clearly.
Maybe it gets lost in translation?