This was with the newer car (2022 Model Y), though I've noticed the same issue on the older car (2017 Model 3) as well.
I searched through the dashcam footage from the Model Y, and indeed the glare is pretty terrible. I'll try cleaning the inner glass and see if it helps. Thanks for the suggestion!
It does bug me that when the warning pops up saying "Camera occluded/blocked/blinded", it doesn't specify WHICH camera! I sort of assumed it wasn't the front camera because the housing and wipers should keep them clean, but evidently not!