Context
Initial setup of Fairphone 6 with Android 15 and August patch.
Symptom
Scanning of home Wi-Fi QR Code doesn’t work in low light conditions, even if brightness of the displaying phone is at maximum.
Workaround
I used a flashlight pointed at the back camera of my Fairphone 6 to provoke a focus adjustment which allowed proper scanning.
More information
As I migrated to /e/OS, I had to repeat the same trick trice due to all reboots. Every time the scan behaved with the same difficulties.
Status
Problem solved for me with the workaround.