The only other place to adjust the volume is the Audio settings within the Zoom Desktop Client. I do not think this will impact your dial-in options either. Specifically, you can follow these steps in the support article below.
Yes indeed, these solutions is working only when you use the desktop client. I tried that without effect. The problem is when you use a dial-in connection with phone number, etc, you don't have any options to manage your own session. I guess the only way is to use the hotkeys on the dial, but that just an idea and supposition. Then I don't have solution to cancel automatic background noise suppression I did not see any global options from the manager of the session to handle this on client seesion ( desktop or dial-in phone session) Thank you Bill for your help