Are you running on Xorg or Wayland? You could test, if it helps to switch to Xorg if you are running on Wayland.
I also read that it can help to set
acpi_backlight=native
as kernel parameter, but I don't know how to do this with rEFInd.
If those ideas don't help, you could try it with brightnessctl or and gnome extension for the brightness to see if it helps. In this thread you see more informations: