I may have the "Ebsv5" series code incorrect. I'd look it up, but I don't have access to the subscription any longer.

What I chose ultimately was definitely "nVME attached" and definitely pricey. The "hypervisor-adjacent, very low latency volume" was not an obvious choice.

The best performing configuration did come from me--the db admin learning Azure on the fly--and not the four Azure architects nor the half dozen consultants with Azure credentials brought onto the project.