Microphone doesn’t work

My iPhone 7 doesn’t have a working microphone, no sound during video. Alexa in Amazon Alexa app turns on for split sec before it’s gone. when I try to use Siri it activates but it doesn’t hear anything, nor will the voice recorder start.

But when I connect my Bluetooth earbuds ( cheap onn earbuds with mic I think) Siri activated and it can hear me and voice recorder works, but when I record video there’s a greyed out slashed speaker symbol at the bottom. Alexa starts but only turns on for split sec.

also when I try to use lightning port to aux or the apple port earbuds , there’s no sound nor do volume buttons work

pls help