Dark mode settings are not responding

(1) Try and Force Restart your iPhone EXACTLY as shown below and see whether that resolves the issue:

• Press and quickly release Volume UP button
• Press and quickly release Volume DOWN button
• Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF). 

(2) After the above has been successfully completed then attempt to change the Dark Mode and see if it works.

Axel F.

Ah, the old smart invert trick which can be mistaken for Dark Mode. Glad you figured it out. You are welcome.

Axel F.