Thanks, it also works on my sideI used this method to root last night and can confirm it works on OB 1 A12. I did the vbmeta part before flashing boot.img and didn't do the vendor_boot part at all.
https://www.droidwin.com/root-android-12-via-magisk-patched-boot-img-without-twrp/ this is the guide I followed.
P.S. On a side note I found it interesting that the "unlocked bootloader" message screen when booting is absent on this new OB1 A12 build. It's kinda nice, I know how much of an eye sore it is for some.