Decided to take a look at Sierra, i had no luck with intelBacklight.kext for brightness, I decided to remove it from L/E and repair cache, and implement the suggested
https://www.tonymacx86.com/threads/...rol-using-applebacklightinjector-kext.218222/
until reboot procedure.
just don't forget to add SSDT-PNLF.aml to your SortedOrder
got the slider working, and now I use the brightness from bergdesign (page 3), fn b (increase) and fn s (decrease) brightness
update 19 July
(addition to brightness) to save previous state of brightness i applied AptioMemoryFix-64.efi (to replace EmuVariableUefi-64.efi) and delete nvram.plist on EFI mount. This EmuVariableUefi-64 doesn't seem to work with xps 13 9343.
updated to latest High Sierra
without APFS conversion, the provided SLE Kexts (which I installed manually with terminal to L/E) except
IOHIDfamily work (it causes External Mouse to stopped working and during kextcache build, it results many errors).
Forget to mention: I check every kexts update, replace all of the Kexts in clover and L/E with the new one. google for the files
I may upload my Clover and the installed kexts in L/E in the future after some other implementations are achieved