DJI hasn't made consumer drones with user-selectable Atti Mode for many years.
Atti Mode is what you have when your drone doesn't have GPS reception (and is unable to use the downward-facing sensors to maintain horizontal position).
Atti Mode =...
On a Mini4P Atti is only a mode that it goes into when GPS signal doesn't meet minimum requirements - AFAIK it is not manually selectable using the regular controller / software.
However that should not cause you great problems flying indoors IF...
A private prison has opened a large immigrant detention center in rural Michigan. I plan to photograph a rally against the detention center on Friday. The problem is that the center itself is in the woods, and not visible from the public road...