Galaxy s7 edge help


Hello Max , i’m new on the forum

I’ve been watching your videos and they are helpful. I have an galaxy s7 edge SM-G935A at&t (unlocked) .I have a different carrier on my phone. Is it possible to unlock boot loader of this phone ?
My phone has 7.0 Nougat right now and i’m wondering how to update it to 8.0 Oreo. How can i upgrade from 7.0 to 8.0 ? Can i flash stock oreo via odin without root ? what are the steps to do this ? i ’ ll be appreciated for any recommendations.

Thank you