If use i3 in newer fedora (f41) the screen brightness automatically increases and then the screen flickers and goes black
This is a known issue that is currently affecting a number of GPUs, it could be related to the power profile that your system is using. If you are able to set your power profile to performance this may avoid the issue for the time being.
There are reports that it may be fixed more permanently in kernel 6.12.9 which will likely arrive in a few weeks: