using external camera and its lapel mic with cam link?

Hi I have an external camera which Im  connecting to zoom via cam link .  

I also have an external microphone but there is a delay . I can clean up this delay but it requires purchasing expensive software (audio hack and loopback which is $156) 

I also have a DJI lapel mic which i can plug into the camera, but when i do that , the video is from the cam link  but the audio is from the internal computer mic. Its as if the lapel mic is not welcome. 

Is there a way to tell zoom to use the audio from the lapel mic and not internal computer microphone when connected via cam link?

I have also tried connecting my external camera via USB and the problem is the same.

Or is there a way to fix the delay for the external mic without purchasing expensive software?

Many thanks