Your question brings up more complexities than you may be looking for.
Off the top of my head, if we study things like the Divine Counsel, God at times in Heaven requests input and decisions from His Counsel. So, in such cases it is God's will to solicit thoughts, input, and decisions and choices from His Counsel from which He will agree or disagree. We can see similarity in how God dealt with Abraham re: Sodom.
Apparently in the past He allowed a portion of the angelic realm to choose to rebel against Him. I don't think it was His will for them to rebel, but it was His will to allow them to choose to do so.
So, I'd say that God does act unilaterally and allows reasoning and choices in the Heavenly realm in similar fashion to what He does here.
So, it looks to me like His will in Heaven is not as simplistic as you may be looking for. In the end, though, based at minimum upon this prayer structure from Jesus I'd have to say Heaven where He sits is greatly preferable to the chaos God has allowed here for a time.
Jesus in Matt6:9 actually commands to pray as He states in the following verses. Not all will choose to pray as He commands.
Men's prayers are actually in the form of commands to God, which carries the concept of pleas, deep longings, reverent requests, urgency and desire. It seems Jesus is instructing that the ultimate order in Heaven is what we should deeply desire here and that our wills should be aligned with God's will.
So, God seems to allow and solicit choice in Heaven as He does here. Heaven seems to be maintained ultimately better and even Satan looks to have had to maintain some decorum in the Heavenly courts. Earth has been for some time a sandbox for unruly volitional creatures to play out the evil that God will ultimately rid His creation of.