To this day, there is no official way to unlock the bootloader of any Nokia/HMD phone. Despite their hollow promises.
This really irks me. On the bright side, they are doing really well with on time updates but hey, allow me to do what I want to do with my phones, at least offer root somewhere deep down in settings so that normal users dont mistakenly enable it.
The standard exuse is that this would be dangerous and result in warranty claims. But other vendors have managed to cope with that. Either they build more robust phones (Google?). Or they register your device id when you request an unlock code. I would accept that, albeit grudgingly.
There is a way, it costs $5 and involves Chinese software on some shady website, but it works, my bootloader is unlocked.
Edit: Ah, you meant Official. My bad.
How do I get something like this with a snapdragon 845? Arm CPUs have taken big steps and there is a big difference between the latest and older CPUs like this.