I want to ask to downgrade my device iPad Air 2 (Cellular)

[Huutanphp]

Hello.
I currently have an iPad Air 2 device (Cellular) running iPadOS 13.3 and recently I saw GeoSn0w's post on youtube on how to downgrade. And I have SHSH2 with iOS 12.1.1 and can I downgrade? If possible, which SEP and baseband do I have to use?

[GeoSn0w]

I am afraid SEP and Baseband are definitely not compatible, so for the moment you can only downgrade fully tethered, if.