Audio drift between camera and mic

I'm new to Davinci and hoping someone can help with an issue I'm having. I'm recording a podcast, usually about 40-50 minutes long. I'm filming on an iPhone (14 I think) using the blackmagic camera app.

I'm recording audio on 2 Behringer mics and a Behringer UMC202HD U-Phoria USB Audio Interface, recording in Audacity.

My issue is, when I import the Audacity audio into Davinci, it starts out synced but ends up drifting so that by the end it's out of sync by a few seconds.

What can I do to prevent this from happening? I have a workflow to fix it in post but it's time-consuming and annoying.

Some less-important info:

For some reason I don't see the waveforms in davinci and the sync doesn't work. I record claps at the start and end but without the waveforms it's frustrating to sync things up.

I'm recording in Audacity at 48,000Hz and I believe the camera is recording at 24fps.