the app will do a lookaround in the environment, knock at ro.debuggable and ro.secure. It will insist on not running on a userdebug build (that community builds are). userdebug builds can be considered “rooted” (via adb).
official builds are “user” builds, but it happened before that some were still a “userdebug” (the first public fp6 build, since resolved)
ps: as to the Google statements of the bank support, unless this is someone who does look at logcat too (and can attribute microg as to what it does), you already know more if you do