Cannot adjust screen brightness OR second screen does not work

Dear all,
I have downloaded and successfully installed Fedora 33 Workstation. At that point, everything was working fine (but the touchpad, but I use a mouse so it doesn’t matter) including the keys to adjust screen brightness.

After performing OS updates, I had the problem that the screen brightness could not be adjusted (when pushing the key, the brightness window pops up and the brightness bar changes, but the screen actually remains on maximum brightness). I then installed nVIDIA drivers (did not help) and found this. Indeed I was in “discrete graphics” mode and switching to “switchable graphics” resolved the brightness problem. However, when in “switchable graphics”, I (only then) have the problem that my external screen does not work.

I am using a Lenovo Legion 5 15ARH05H with GeForce RTX 2060 and AMD Ryzen 7 4800h with radeon graphics.

Does anyone know this problem? I would also be fine with downgrading to the Fedora33 version I had when installing it, however I don’t know how good or bad this is security-wise.

I have also checked out this answer from ask.fedoraproject. Using xrandr --output DP-2 --brightness 0.6 works (in discrete graphics mode) but it is not an optimal solution IMO. Alessio’s answer in the same thread (answer #8) did not work because neither /etc/X11/nvidia-xorg.conf nor /etc/X11/xorg.conf.d/98-nvidia-xorg.conf exist.

Thanks for any advice!