No thumbnail or image file when shooting DNG from Lightroom

When I shoot a DNG file in Lightroom on iPhone 11Pro, no thumbnail appears in the app and I can't locate the DNG file anywhere. I have a subscription to LR and LR Classic, am logged in, and sync is on.  I tried shooting a JPG from LR instead and that thumbnail appears immediately (next to the camera in LR and in "Lr Camera Photos") and I can edit the JPG in LR on my phone.  The JPG is not syncing to LR Classic on my desktop though, even though it says sync'd and saved.  So I'd like to figure out 1) why can't I see the DNG image at all when I'm on Lightroom on my phone? 2) And why aren't the images (DNG or JPG) syncing and appearing in my catalog on my desktop?