https://bugzilla.kernel.org/show_bug.cgi?id=207833
--- Comment #2 from julen.pardo@outlook.es --- (In reply to Mateusz from comment #1)
Does it work better after closing lid and reopen it? (the system goes suspend) I have an ASUS Zephyrus G14 with similar specs and this is the case, after closing lid and suspending when I wake up the system brightness control works good.
Not really, it's the same. Actually I just get a blackscreen and I need to shut it down :)
But I've discovered something interesting. If I first boot into the Windows partition and then reboot into the Linux one, the brightness control works fine.