Message notifications chime despite being disabled

Since upgrading my Macbook Pro 2019 to Monterey, I've been receiving intermittent text chimes (the default message audible notification) despite having disabled this in preferences. It doesn't happen for every single incoming message, but roughly 1 in 5. For whatever reason, this sound scares my dog, and it's getting really irritating that I can't disable the sound fully. I would like to continue receiving banner notifications visually. I obviously don't get the chime if the computer is muted, but it'd be cool if I could, you know, listen to music.

Under Notifications & Focus>Messages, I have unchecked "Play sound for notifications."

I would even settle for changing the message notification sound to a different sound (I did this easily on my iPhone) but I can't find that setting either. I'm stumped and my dog is miserable. Please help.