To change your default Google account, you'll first need to sign out of all of your Google accounts.

On iOS, most Google apps now have this Account menu redesign. Gemini, Google Home, Photos, and Translate put many items in the account menu. In comparison, Google Workspace apps — Docs, Drive, Gmail, ...

Google Chrome allows you to sign into multiple Google accounts, but you can remove them at any time, as well as disable ...

The fullscreen Google Account switcher started rolling out earlier this year, and the menu redesign is now coming to the remaining apps.