No, no, no: backstabbing Austria is the way to go.
There are no interesting provinces of Burgundy for the taking, perhaps a few in northern Germany but that's about it.
Austria on the other hand has been a powerfull thorn on your weakest side for almost 100 years now.
They have 3 (i think) very juicy gold provinces sitting right there in plain sight.
And since the Ottomans and Mamluks are now at each others throat, there is no real danger in the Ottomans knocking on your back door.