Hello, sorry to hear you are experiencing this issue. When you open the camera app, and click on photo, there should be a gear icon on the upper left hand side. If you click on that, it will take you to camera settings. If you scroll to the bottom and click "reset camera settings" this may solve your issue. I hope that helps.
Looks like it's an issue with the camera software on One UI 2.1. Ever since I updated my Note 10+, I'm seeing the same thing under certain circumstances: everything gets a yellow/green tint. The camera software is failing to meter white balance correctly, especially when looking at tan tones. It hunts around, looking for the correct value, until you press the shutter and take your chances. Samsung probably won't fix the issue.
A workaround is to shoot in Pro mode and set the white balance to something that actually resembles what your eyes see in the scene. Samsung is REALLY screwing up the camera basics this year.
We are having the same issue on our two S20 Plus. Both of them have this very yellow tint (at least on the rear camera). Very annoying, both of us had S10 plus before and they did not have this extreme yellow tint. Samsung really scr*wed up the cameras this year.