Help...??? Recording VO directly into FCPX is somehow "slower?"

Hello - I just upgraded to a new iPhone 12, and the new M1 mini (with latest FCPX software). 

When producing videos, I used to use my iphone 11 to record the video, while recording audio through FCPX (voice over) - at the same time. That way, my better mic - which was hooked in through my audio interface - could be used.I'd then just import my video, sync up and delete the iphone audio. Worked perfect.Until now...Now, when I record via FCPX voice over, while recording video on my iphone 12, and import the video - the audio drifts out of sync very quickly. It's like the FCPX VO recording is much "slower."I tried this *multiple* times - with the following changes:

1. Changed project audio rate settings from 48 to 44.1 (no effect)
2. Changed my phone settings to:  not be HDR, "most compatible" format, 4k - 24 and 30fps settings, and also just regular HD instead of 4k - (no effect)
3. Changed project from 24fps to 30fps
4. Used Handbrake to modify/export the video again to constant frame rate

As another test - I recorded audio into QT, and screen recording into QT (using audio from my audio interface) - and the QT audio syncs up with the iphone footage. (This is the photo I uploaded - which shows how the QT screen recording is totally lined up with the iphone footage. It's just the VO directly into FCPX that's still "off.")

Per the QT audio/screen recording test - since that lines up fine with the iPhone 12 footage - it seems like the problem is recording VO directly into FCPX.  What I don't understand, is why just upgrading messed this all up. I used to do this method ALL THE TIME, with no problems before.

I **really** would love to keep using the direct VO into FCPX, so that my VO recording as with the same mic and settings as when I use my camera. And really don't want to be cutting up little bits of audio from the VO to sync up with the video.Anyone know how to help???