Oh, dude, the proper adjective for Siberia is "Siberian." Like, you wouldn't want to call it "Siberia-ish" or "Siberia-esque," that would just be weird. So yeah, just stick with "Siberian" and you'll sound like you kinda know what you're talking about.
Related Q&A：
What is the proper adjective for siberia？-Oh boy, the proper adjective for Siberia is \Siberian\ You know, when we talk about things related to Siberia, we often use \Siberian\ to describe them. For example, we might say \Siberian weather\ if we're referring to the climate in that region. Or \Siberian tigers\ when we talk about those magnificent big cats that are native to parts of Siberia. Isn't that interesting? So, whenever you want to describe something specifically from or related to Siberia, \Siberian\ is the word you should go for.
