Change JUST the date capture time?

After shooting a wedding, I realized that half of the photos my second shooter made were on a camera with the incorrect date and time. (Even after asking her to sync it, she only synced one camera, ugh.) I need to be able to change hundreds/thousands of photos, and I thought this would be relatively easy, but I'm hitting snags.

I can change the capture time, but either shift just the time of day by hours/minutes, or set them all to the exact same date and time. I need to first change the date, then separately shift the time. Is this possible?

I tried converting the number of days into hours, and shifting the time by that number of hours, but there's a limit of 24 hours to shift. I tried just changing the date, but then it changes all the photos to the exact same time of day ALONG with the date.

Can anyone help me figure this out?