On an iPad running iOS 26.0.1 & Brave 1.82.1 (174), you’re able to access private tabs without a finger print or lock code requirement if you press and hold the new tab icon (+) and select New Private Tab
I’m reading this as a statement and not a question…
If you just want to add Touch/Face ID for your Private Tabs:
Open a “New Tab Page (by pressing the + button) > three dots menu > All Settings > Private Tabs (close to the very bottom) > Toggle Require Touch/Face ID.
&/OR
Update to 1.83 / in the newly designed “Tab Selection Page” (after clicking the box with the number to the right of the + button, e.g. [1] ) > More (at the bottom left) > Private Tabs Settings > Toggle Require Touch/Face ID.