Because I cannot reply to the thread talking about this problem, I am opening a new thread with the solution to your Galaxy Note 20 Ultra camera app opening on its own. This was a gigantic problem for me when I was moving from Texas to North Carolina. Having to constantly go to the picture in picture and expand it to see where I was going, especially in traffic in Houston and Atlants, was beyond dangerous.
I figured this out by noticing that the problem didn't happen when the S Pen was not connected (another of the myriad of problems I have had with both this phone and Samsung corporate in general in the last year, it's been so bad I am seriously looking into getting an iPhone next, oh the shame). /rant
Basically, I solved the problem by turning off Air Actions in the S Pen settings. Ever since I did this, I have not experienced the problem.