I've read at least three other posts about the inability to change notification sounds. Each thread got a typical BS response from the Google moderator --thanks for the comment, they'll say -- and close the thread.
Instead, why don't you take the feedback to the Google Camera and Doorbell developers? Now that would be helpful.
Thanks for your patience. I appreciate you sharing the case id you’ve been working on. As I’ve checked, our team has identified the issue and is currently working on a fix. Rest assured we're on top of this. I'll go ahead and lock this thread after 24 hours, and let's continue through that channel. Should you have any questions, feel free to let me know.