Use an IMAP client. There's multiple available for both mobile and desktop operating systems. You'll need to turn IMAP on in the settings menu of the Gmail web page, and for clients that don't support OAuth2, you'll need to create application-specific passwords, in the Google Accounts web page.
As an added bonus, pretty much every IMAP client is faster, has more reliable notifications, and better usability/accessibility than Google's web interface and mobile applications.
I doubt they will offer a way, they need free training material since you use their “free” product
Had the same question, lmk if you find the magical "off" switch
edit: apparently it's turning into a bit of a disaster for Google, cos everyone wants it off:
https://bsky.app/profile/litbowl.bsky.social/post/3lfvlw656x...
Workspace admins have a bunch of Gemini checkboxes but none of them actually seem to disable Gemini.
They're making it a forced upgrade so they can charge more for email accounts. +$2/user/month is what they want for Gemini.