It appears to me you might be making this a lot more difficult than necessary. Why not just pre-create the required partitions daily or weekly or monthly? Or do you have a requirement that a new partition only be created the first time it is required?
+1
we create new partitions in advance of their being needed as part of a maintenance process that's strictly single threaded.
While I've been trying to explain the mechanics involved here I agree that the whole idea of exceptionally creating a table in a trigger is just asking for trouble. I do get the idea of not wanting an external maintenance process involved that needs to be setup and maintained, and maybe there are now better options with "workers", but the trade-offs involved would start leaning me heavily toward having a maintenance routine, especially in a production environment, and at that point you should mirror production in development.