When you go into settings to change the brightness of the instrument panel backlite is this change permanent or does it only last until you turn the power off? --thanks--

 

Should stay how you set it in he settings menu

 

My ‘22 Hybrid Touring retains the setting unless the 12V battery is disconnected which causes a reset to default. However, there are two modes, day and night and it may also be affected by parking/headlight status.
The Model you have and your definition of “power off” is likely to influence the answer to your question.