I have also Note 10 Lite and haven't noticed such difference in video recording prior to update Vs after update.
What settings you are using in video recording ?
Let me know here so that I can also check in my phone.
Also escalate this to higher level Samsung by writing to service head and write to ceo.
Send request via members app as well.
Ask for immediate replacement as this issue is affecting your work.
if u want to try it then just put the phone on phone stand and make a video in pure white background or in front of white board. when you record the video just turn your face some times for white background and some time face the camera.
But effects are as major as in your video.
May be due to lighting conditions difference.
I think issue is related to auto detection of face while video capture.
They should allow this thing to be disabled.
Dear Samsung Member,
Greetings from Samsung Customer Support!
Please perform the below mentioned steps to resolve the issue:
* Reset camera settings
Camera > Settings > Reset settings > Reset.
For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).
Thank you for writing to Samsung.
Samsung Customer Support