Hello Allison, sorry about your problems. My name is Marco and I will do my best to help you.
Recent iOS videos use the HEVC codec by default.
Installing the HEVC Video Extensions from the Microsoft Store might help preserve the original date when transferring videos.
You can find it here: https://www.microsoft.com/store/productId/9NMZL...
After restarting the photos app the videos are transferred with the correct date.