First attempts to fixing
The fix (wip, hopefully coming)
This is a common problem in recent distributives of linux, according to my searches online.
After a fresh installation of Mint (xfce version, a very pleasant lightweight operating system) on [yet another] my laptop, I noticed that the brightness of the monitor was low.
Sometimes the system did respond to pressing brightness buttons on the keyboard (Fn+Brightness Up/Down), but the response was weird and chaotic.