Download official Oreo from Sammy's and flash it with Odin. Than install TWRP - also with Odin, boot to TWRP, flash no-verity-opt-encrypt-6.0, format data, reboot to twrp, do all the wipes, install GoogleWiz.
No man, I wish it were that simple. If i simply try to flash official oreo through odin, on normal odin it fails, when I use prince comsy's it completes it vert fast and says pass, but doesn't really change a thing apart from making the phone restart back into pie. I think I need to downgrade modem and bootloader or something like what is CL1 or CL3 i have no clue.. :/